Question

我创建了一个类似联系人列表的程序。到目前为止，我已经能够添加或更新联系人，但我无法删除联系人。我不知道问题出在哪里。当我要进入DisplayContact类时，我会遇到ForceClose。

我的DisplayContact代码：

public class DisplayContact extends Activity { 

 int from_Where_I_Am_Coming = 0;
    private DBHelper mydb ;

    TextView name ;
    TextView phone;
    TextView email;
    TextView street;
    TextView place;
    int id_To_Update = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_display_contact);
        name = (TextView) findViewById(R.id.editTextName);
        phone = (TextView) findViewById(R.id.editTextPhone);
        email = (TextView) findViewById(R.id.editTextStreet);
        street = (TextView) findViewById(R.id.editTextEmail);
        place = (TextView) findViewById(R.id.editTextCity);

        mydb = new DBHelper(this);

        Bundle extras = getIntent().getExtras();
        if(extras !=null) {
            int Value = extras.getInt("id");

            if(Value>0){
                //means this is the view part not the add contact part.
                Cursor rs = mydb.getData(Value);
                id_To_Update = Value;
                rs.moveToFirst();

                String nam = rs.getString(rs.getColumnIndex(DBHelper.CONTACTS_COLUMN_NAME));
                String phon = rs.getString(rs.getColumnIndex(DBHelper.CONTACTS_COLUMN_PHONE));
                String emai = rs.getString(rs.getColumnIndex(DBHelper.CONTACTS_COLUMN_EMAIL));
                String stree = rs.getString(rs.getColumnIndex(DBHelper.CONTACTS_COLUMN_STREET));
                String plac = rs.getString(rs.getColumnIndex(DBHelper.CONTACTS_COLUMN_CITY));

                if (!rs.isClosed())  {
                    rs.close();
                }
                Button b = (Button)findViewById(R.id.button1);
                b.setVisibility(View.VISIBLE);

                name.setText((CharSequence)nam);
                name.setFocusable(true);
                name.setClickable(true);

                phone.setText((CharSequence)phon);
                phone.setFocusable(true);
                phone.setClickable(true);

                email.setText((CharSequence)emai);
                email.setFocusable(false);
                email.setClickable(false);

                street.setText((CharSequence)stree);
                street.setFocusable(false);
                street.setClickable(false);

                place.setText((CharSequence)plac);
                place.setFocusable(false);
                place.setClickable(false);
            }

            Button b2 = (Button)findViewById(R.id.button2);
            b2.setVisibility(View.VISIBLE);

            name.setText((CharSequence)name);
            name.setFocusable(true);
            name.setClickable(true);

            phone.setText((CharSequence)phone);
            phone.setFocusable(true);
            phone.setClickable(true);

            email.setText((CharSequence)email);
            email.setFocusable(false);
            email.setClickable(false);

            street.setText((CharSequence)street);
            street.setFocusable(false);
            street.setClickable(false);

            place.setText((CharSequence)place);
            place.setFocusable(false);
            place.setClickable(false);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        Bundle extras = getIntent().getExtras();

        if(extras !=null) {
            int Value = extras.getInt("id");
            if(Value>0){
                getMenuInflater().inflate(R.menu.display_contact, menu);
            } else{
                getMenuInflater().inflate(R.menu.main_menu, menu);
            }
        }
        return true;
    }

    public boolean onOptionsItemSelected(MenuItem item) {
        super.onOptionsItemSelected(item);
        switch(item.getItemId()) {
            case R.id.Edit_Contact:

                Button b = (Button)findViewById(R.id.button1);
                b.setVisibility(View.VISIBLE);

                name.setEnabled(true);
                name.setFocusableInTouchMode(true);
                name.setClickable(true);

                phone.setEnabled(true);
                phone.setFocusableInTouchMode(true);
                phone.setClickable(true);

                email.setEnabled(true);
                email.setFocusableInTouchMode(true);
                email.setClickable(true);

                street.setEnabled(true);
                street.setFocusableInTouchMode(true);
                street.setClickable(true);

                place.setEnabled(true);
                place.setFocusableInTouchMode(true);
                place.setClickable(true);


            case R.id.Delete_Contact:

                Button b1 = (Button)findViewById(R.id.button2);
                b1.setVisibility(View.VISIBLE);

                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                builder.setMessage(R.string.deleteContact)
                        .setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                mydb.deleteContact(id_To_Update);
                                Toast.makeText(getApplicationContext(), "Deleted Successfully",
                                        Toast.LENGTH_SHORT).show();
                                Intent intent = new Intent(getApplicationContext(),MainActivity.class);
                                startActivity(intent);
                            }
                        })
                        .setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {

                            }
                        });

                AlertDialog d = builder.create();
                d.setTitle("Are you sure");
                d.show();

                return true;
            default:
                return super.onOptionsItemSelected(item);

        }
    }

    public void run(View view) {
        Bundle extras = getIntent().getExtras();
        if(extras !=null) {
            int Value = extras.getInt("id");
            if(Value>0){
                if(mydb.updateContact(id_To_Update,name.getText().toString(),
                        phone.getText().toString(), email.getText().toString(),
                        street.getText().toString(), place.getText().toString())){
                    Toast.makeText(getApplicationContext(), "Updated", Toast.LENGTH_SHORT).show();
                    Intent intent = new Intent(getApplicationContext(),MainActivity.class);
                    startActivity(intent);
                } else{
                    Toast.makeText(getApplicationContext(), "not Updated", Toast.LENGTH_SHORT).show();
                }
            } else{
                if(mydb.insertContact(name.getText().toString(), phone.getText().toString(),
                        email.getText().toString(), street.getText().toString(),
                        place.getText().toString())){
                    Toast.makeText(getApplicationContext(), "done",
                            Toast.LENGTH_SHORT).show();
                } else{
                    Toast.makeText(getApplicationContext(), "not done",
                            Toast.LENGTH_SHORT).show();
                }
                Intent intent = new Intent(getApplicationContext(),MainActivity.class);
                startActivity(intent);
            }
        }
    }
}

Answer 1

不确定你要删除的内容，但在数据库帮助文件中，我会做出类似的结果。

    public void deleteRecordID(int id){
    String query = "DELETE FROM "+ TABLE_NAME +" WHERE " + ID+" = "+id;
    SQLiteDatabase db = this.getWritableDatabase();
    db.execSQL(query);
    db.close();
}

并将值传递给下面的ID，我无法找到你的抓取方法，但这是你如何从sqlite数据库中删除

DatabaseHelper db;
db = new DatabaseHelper(v.getContext());
db.deleteRecordID(id);

Answer 2

我的MainActivity代码：

public final static String EXTRA_MESSAGE = "MESSAGE";
private ListView obj;
DBHelper mydb;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mydb = new DBHelper(this);
    ArrayList array_list = mydb.getAllCotacts();
    ArrayAdapter arrayAdapter=new ArrayAdapter(this,android.R.layout.simple_list_item_1, array_list);

    obj = (ListView)findViewById(R.id.listView1);
    obj.setAdapter(arrayAdapter);
    obj.setOnItemClickListener(new OnItemClickListener(){
        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,long arg3) {
            // TODO Auto-generated method stub
            int id_To_Search = arg2 + 1;

            Bundle dataBundle = new Bundle();
            dataBundle.putInt("id", id_To_Search);

            Intent intent = new Intent(getApplicationContext(),DisplayContact.class);

            intent.putExtras(dataBundle);
            startActivity(intent);
        }
    });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main_menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item){
    super.onOptionsItemSelected(item);

    switch(item.getItemId()) {
        case R.id.item1:Bundle dataBundle = new Bundle();
            dataBundle.putInt("id", 0);

            Intent intent = new Intent(getApplicationContext(),DisplayContact.class);
            intent.putExtras(dataBundle);

            startActivity(intent);
            return true;
        default:
            return super.onOptionsItemSelected(item);
    }
}

public boolean onKeyDown(int keycode, KeyEvent event) {
    if (keycode == KeyEvent.KEYCODE_BACK) {
        moveTaskToBack(true);
    }
    return super.onKeyDown(keycode, event);
}

}

从SQLite数据库中删除项目

2 个答案: