Question

我使用SQLite数据库来保存我应用中不同活动的数据。在第一个活动中，我使用add方法在表中创建一行，下一个活动使用update方法更新创建的列。我之前的问题在某种程度上类似，可以在这里找到：
Previous Question

以前我的问题是没有使用setId。现在我的问题是第三项活动。调用update方法后，列保持 Null 。我尝试将id从NewProjectActivity传递给MainActivity，然后传递给IntensityActivity，但我不知道为什么列不会更新。以下是代码：

SQLite Helper：

public class SQLiteHelper extends SQLiteOpenHelper implements ProjectDAO {

    public SQLiteHelper(Context context) {
        super(context, "my_db", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        try {
            db.execSQL("CREATE TABLE tbl_project_info (id INTEGER PRIMARY KEY," +
                    "name TEXT," +
                    "company_name TEXT," +
                    "address TEXT," +
                    "length1 TEXT," +
                    "length2 TEXT," +
                    "length3 TEXT," +
                    "length4 TEXT," +
                    "length5 TEXT," +
                    "diameter1 Text," +
                    "diameter2 Text," +
                    "diameter3 Text," +
                    "diameter4 Text," +
                    "diameter5 Text," +
                    "surface Text," +
                    "soilResistance Text," +
                    "intensity Text," +
                    "allowedIntensity Text," +
                    "intensityResult Text)");
        } catch (SQLiteException e) {
            Log.e("SQLITE", "onCreate: " + e.toString());
        }

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    @Override
    public long addProject(Project project) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put("name", project.getName());
        contentValues.put("company_name", project.getCompany_name());
        contentValues.put("address", project.getAddress());
        contentValues.put("length1", project.getLength1());
        contentValues.put("length2", project.getLength2());
        contentValues.put("length3", project.getLength3());
        contentValues.put("length4", project.getLength4());
        contentValues.put("length5", project.getLength5());
        contentValues.put("diameter1", project.getDiameter1());
        contentValues.put("diameter2", project.getDiameter2());
        contentValues.put("diameter3", project.getDiameter3());
        contentValues.put("diameter4", project.getDiameter4());
        contentValues.put("diameter5", project.getDiameter5());
        contentValues.put("surface", project.getSurface());
        contentValues.put("soilResistance", project.getSoilResistance());
        contentValues.put("intensity", project.getIntensity());
        contentValues.put("allowedIntensity", project.getAllowedIntensity());
        contentValues.put("intensityResult", project.getIonS());
        long result = db.insert("tbl_project_info", null, contentValues);
        db.close();
        return result;
    }

    @Override
    public int getProjectsCount() {
        SQLiteDatabase db = getReadableDatabase();
        Cursor cursor = db.rawQuery("SELECT * FROM tbl_project_info", null);
        int count = cursor.getCount();
        cursor.close();
        db.close();
        return count;
    }

    @Override
    public boolean updateProject(Project project) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put("length1", project.getLength1());
        contentValues.put("length2", project.getLength2());
        contentValues.put("length3", project.getLength3());
        contentValues.put("length4", project.getLength4());
        contentValues.put("length5", project.getLength5());
        contentValues.put("diameter1", project.getDiameter1());
        contentValues.put("diameter2", project.getDiameter2());
        contentValues.put("diameter3", project.getDiameter3());
        contentValues.put("diameter4", project.getDiameter4());
        contentValues.put("diameter5", project.getDiameter5());
        contentValues.put("surface", project.getSurface());
        contentValues.put("soilResistance", project.getSoilResistance());
        contentValues.put("intensity", project.getIntensity());
        contentValues.put("allowedIntensity", project.getAllowedIntensity());
        contentValues.put("intensityResult", project.getIonS());
        db.update("tbl_project_info", contentValues, "id = ?", new String[]{String.valueOf(project.getId())});
        db.close();
        return true;
    }

    @Override
    public List<Project> getAllProjects() {
        List<Project> projects = new ArrayList<>();
        SQLiteDatabase db = getReadableDatabase();
        Cursor cursor = db.rawQuery("SELECT * FROM tbl_project_info", null);
        if (cursor.moveToFirst()) {
            do {
                Project project = new Project();
                project.setName(cursor.getString(0));
                project.setCompany_name(cursor.getString(1));
                project.setAddress(cursor.getString(2));
                projects.add(project);
            } while (cursor.moveToNext());
        }
        return projects;
    }
}

NewProjectActivity：

public class NewProjectActivity extends AppCompatActivity {
    private ProjectDAO projectDAO;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_new_project);
        projectDAO = DBInjector.provideProjectDao(this);
        setupViews();
    }

    private void setupViews() {
        final EditText projectNameET = findViewById(R.id.et_newProject_projectName);
        final EditText companyNameET = findViewById(R.id.et_newProject_companyName);
        final EditText addressET = findViewById(R.id.et_newProject_address);
        Button saveInfoBTN = findViewById(R.id.btn_newProject_saveInfo);

        saveInfoBTN.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                long projectID = -1;
                if (projectNameET.length() > 0) {
                    if (companyNameET.length() > 0) {
                        if (addressET.length() > 0) {
                            Project project = new Project();
                            project.setName(projectNameET.getText().toString());
                            project.setCompany_name(companyNameET.getText().toString());
                            project.setAddress(addressET.getText().toString());
                            projectID = projectDAO.addProject(project);
                            if (projectID > 0){
                                Toast.makeText(NewProjectActivity.this, "Success", Toast.LENGTH_SHORT).show();
                            }else {
                                Toast.makeText(NewProjectActivity.this, "Failed", Toast.LENGTH_SHORT).show();
                            }

                        }
                        }else {
                        companyNameET.setError("company name not entered");
                    }

                    }else{
                    projectNameET.setError("project name not entered");
                }

                PersonalInfoSharedPrefManager manager = new PersonalInfoSharedPrefManager(NewProjectActivity.this);
                manager.setID(projectID);


                Intent intent = new Intent(NewProjectActivity.this,MainActivity.class);
                intent.putExtra("IE_PROJECTID",projectID);
                startActivity(intent);
                }
            });
        }
    }

MainActivity：

public class MainActivity extends AppCompatActivity {
    private ProjectDAO projectDAO;
    private long mProjectID;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        projectDAO = DBInjector.provideProjectDao(this);
        mProjectID = getIntent().getLongExtra("IE_PROJECTID",0);

        final EditText lengthET1 = findViewById(R.id.et_main_length1);
        final EditText lengthET2 = findViewById(R.id.et_main_length2);
        final EditText lengthET3 = findViewById(R.id.et_main_length3);
        final EditText lengthET4 = findViewById(R.id.et_main_length4);
        final EditText lengthET5 = findViewById(R.id.et_main_length5);
        final EditText diameterET1 = findViewById(R.id.et_main_diameter1);
        final EditText diameterET2 = findViewById(R.id.et_main_diameter2);
        final EditText diameterET3 = findViewById(R.id.et_main_diameter3);
        final EditText diameterET4 = findViewById(R.id.et_main_diameter4);
        final EditText diameterET5 = findViewById(R.id.et_main_diameter5);

        Button calculateButton = findViewById(R.id.btn_main_calculate);
        calculateButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                float Le1 = 0;
                if (lengthET1.length() > 0) {
                    String L1 = lengthET1.getText().toString();
                    Le1 = Float.parseFloat(L1);
                }
                float Di1 = 0;
                if (diameterET1.length() > 0) {
                    String D1 = diameterET1.getText().toString();
                    Di1 = Float.parseFloat(D1);
                }
                float Le2 = 0;
                if (lengthET2.length() > 0) {
                    String L2 = lengthET2.getText().toString();
                    Le2 = Float.parseFloat(L2);
                }
                float Di2 = 0;
                if (diameterET2.length() > 0) {
                    String D2 = diameterET2.getText().toString();
                    Di2 = Float.parseFloat(D2);
                }
                float Le3 = 0;
                if (lengthET3.length() > 0) {
                    String L3 = lengthET3.getText().toString();
                    Le3 = Float.parseFloat(L3);
                }
                float Di3 = 0;
                if (diameterET3.length() > 0) {
                    String D3 = diameterET3.getText().toString();
                    Di3 = Float.parseFloat(D3);
                }
                float Le4 = 0;
                if (lengthET4.length() > 0) {
                    String L4 = lengthET4.getText().toString();
                    Le4 = Float.parseFloat(L4);
                }
                float Di4 = 0;
                if (diameterET4.length() > 0) {
                    String D4 = diameterET4.getText().toString();
                    Di4 = Float.parseFloat(D4);
                }
                float Le5 = 0;
                if (lengthET5.length() > 0) {
                    String L5 = lengthET5.getText().toString();
                    Le5 = Float.parseFloat(L5);
                }
                float Di5 = 0;
                if (diameterET5.length() > 0) {
                    String D5 = diameterET5.getText().toString();
                    Di5 = Float.parseFloat(D5);
                }

                final float Surface1 = (float) (Le1 * Di1 * Math.PI);
                final float Surface2 = (float) (Le2 * Di2 * Math.PI);
                final float Surface3 = (float) (Le3 * Di3 * Math.PI);
                final float Surface4 = (float) (Le4 * Di4 * Math.PI);
                final float Surface5 = (float) (Le5 * Di5 * Math.PI);

                final float Surface = Surface1 + Surface2 + Surface3 + Surface4 + Surface5;
                long projectID = -1;

                Intent intent = new Intent(MainActivity.this, IntensityActivity.class);
                if (Surface == 0) {
                    Toast.makeText(MainActivity.this, "No numbers are entered", Toast.LENGTH_SHORT).show();
                } else {
                    intent.putExtra("Result", Surface);
                    intent.putExtra("IE_PROJECTID",projectID);
                    startActivity(intent);
                }
                PersonalInfoSharedPrefManager manager = new PersonalInfoSharedPrefManager(MainActivity.this);
                manager.setSuface(Surface);


                Project project = new Project();
                project.setId(mProjectID);

                project.setLength1(lengthET1.getText().toString());
                project.setDiameter1(diameterET1.getText().toString());

                project.setLength2(lengthET2.getText().toString());
                project.setDiameter2(diameterET2.getText().toString());

                project.setLength3(lengthET3.getText().toString());
                project.setDiameter3(diameterET3.getText().toString());

                project.setLength4(lengthET4.getText().toString());
                project.setDiameter4(diameterET4.getText().toString());

                project.setLength5(lengthET5.getText().toString());
                project.setDiameter5(diameterET5.getText().toString());

                project.setSurface(String.valueOf(Surface));

                projectDAO.updateProject(project);
            }
        });
    }
}

IntensityActivity：

public class IntensityActivity extends AppCompatActivity {
    private ProjectDAO projectDAO;
    private long mProjectID;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_intensity);
        projectDAO = DBInjector.provideProjectDao(this);
        mProjectID = getIntent().getLongExtra("IE_PROJECTID",0);

        final float Result = getIntent().getFloatExtra("Result",0);

        final Button resistanceBTN1 = findViewById(R.id.btn_intensity_R1); 
        final Button resistanceBTN2 = findViewById(R.id.btn_intensity_R2);
        final Button resistanceBTN3 = findViewById(R.id.btn_intensity_R3); 
        final Button resistanceBTN4 = findViewById(R.id.btn_intensity_R4); 
        final Button resistanceBTN5 = findViewById(R.id.btn_intensity_R5);
        final View RL = findViewById(R.id.rl_intensity_allowedIntensity);
        final TextView allowedResistance = findViewById(R.id.tv_intensity_allowedIntensityNumber);
        final TextView surfaceNumber = findViewById(R.id.tv_intensity_surfaceNumber);
        final EditText intensityNumber = findViewById(R.id.et_intensity_intensityNumber); 
        Button calculateButton = findViewById(R.id.btn_intensity_calculate); 
        final Button goToVoltageButton = findViewById(R.id.btn_intensity_goToVoltage);
        final TextView formulaResultNumber = findViewById(R.id.tv_intensity_resultNumber);
        String Sur = Float.toString(Result);
        surfaceNumber.setText(Sur);

        final double R1 = Result*0.250;
        final double R2 = Result*0.125;
        final double R3 = Result*0.050;
        final double R4 = Result*0.025;
        final double R5 = Result*0.010;
        final String Re1 = Double.toString(R1);
        final String Re2 = Double.toString(R2);
        final String Re3 = Double.toString(R3);
        final String Re4 = Double.toString(R4);
        final String Re5 = Double.toString(R5);

        resistanceBTN1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                RL.setVisibility(View.VISIBLE);
                allowedResistance.setText(Re1);
            }
        });
        resistanceBTN2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                RL.setVisibility(View.VISIBLE);
                allowedResistance.setText(Re2);
            }
        });
        resistanceBTN3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                RL.setVisibility(View.VISIBLE);
                allowedResistance.setText(Re3);
            }
        });
        resistanceBTN4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                RL.setVisibility(View.VISIBLE);
                allowedResistance.setText(Re4);
            }
        });
        resistanceBTN5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                RL.setVisibility(View.VISIBLE);
                allowedResistance.setText(Re5);
            }
        });

        calculateButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String I = intensityNumber.getText().toString();
                float In = Float.parseFloat(I);
                float R = In/Result;
                String Res = String.valueOf(R);
                formulaResultNumber.setText(Res);
                goToVoltageButton.setVisibility(View.VISIBLE);

                PersonalInfoSharedPrefManager manager = new PersonalInfoSharedPrefManager(IntensityActivity.this);
                manager.setIntensity(In);


            }
        });

        goToVoltageButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(IntensityActivity.this,SimpleVoltage.class);
                startActivity(intent);

                Project project = new Project();
                project.setId(mProjectID);

                project.setAllowedIntensity(String.valueOf(allowedResistance));
                project.setIntensity(intensityNumber.getText().toString());

                projectDAO.updateProject(project);
            }
        });

    }
}

Answer 1

从MainActivity到IntensityActivity，我发现你总是在项目ID中传递-1

final float Surface = Surface1 + Surface2 + Surface3 + Surface4 + Surface5;
                long projectID = -1;

                Intent intent = new Intent(MainActivity.this, IntensityActivity.class);
                if (Surface == 0) {
                    Toast.makeText(MainActivity.this, "No numbers are entered", Toast.LENGTH_SHORT).show();
                } else {
                    intent.putExtra("Result", Surface);
                    intent.putExtra("IE_PROJECTID",projectID);
                    startActivity(intent);
                }

相反，您可以从Intent

传递此活动所获得的相同ID

只需在MainActivity中更新您的代码，如下所示，然后传递mProjectID。

 final float Surface = Surface1 + Surface2 + Surface3 + Surface4 + Surface5;
                long projectID = -1;

                Intent intent = new Intent(MainActivity.this, IntensityActivity.class);
                if (Surface == 0) {
                    Toast.makeText(MainActivity.this, "No numbers are entered", Toast.LENGTH_SHORT).show();
                } else {
                    intent.putExtra("Result", Surface);
                    intent.putExtra("IE_PROJECTID",mProjectID);
                    startActivity(intent);
                }

希望这会有所帮助。

Answer 2

在您的更新方法中尝试这种方式，

 db.update("tbl_project_info", contentValues, "id="+String.valueOf(project.getId()), null);

您还需要将以下行更改为MainActivity.java

long projectID = -1;

到

long projectID = mProjectID;

SQLite数据库列在不同活动中的更新方法上保持空

2 个答案: