Question

我试图从另一个类中获取一个字符串，并在MainActivity中使用它。该字符串在OnItemClickListener内部的OnClickListener中初始化。我搜索了一些解决方案，但是使用Intent的方法在这里不起作用，因为我没有在活动之间进行切换，而是希望MainActivity中的String。我尝试使用SharedPreferences的方法，但是没有用。这是带有字符串的类的代码

TimeForm

public class TimeForm extends AppCompatActivity{

public ArrayList<String> arrayList;
ListView dayListView;
ArrayAdapter<String> arrayAdapter;
private static List<String> fromArrayList;
ArrayList<String> untilArrayList;
public String currentDay;
EditText fromEditText;
EditText untilEditText;
EditText multiLineEditText;
ListView itemsListView;
Button submitButton;
EditText actionEditText;
private FirebaseFirestore db;
private static final String TAG = "TimeForm";

public String CurrentDay;


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

    //Variables==============================================================
    dayListView = (ListView)findViewById(R.id.dayListView);
    arrayList = new ArrayList<String>();
    final TextView dayTextView = (TextView)findViewById(R.id.dayTextView);
    submitButton = (Button)findViewById(R.id.submitButton);
    fromEditText = (EditText)findViewById(R.id.fromEditText);
    multiLineEditText = (EditText)findViewById(R.id.actionEditText);
    untilEditText = (EditText)findViewById(R.id.untilEditText);
    arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, arrayList);
    fromArrayList = new ArrayList<String>();
    untilArrayList = new ArrayList<String>();
    final ArrayAdapter fromArrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, fromArrayList);
    ArrayAdapter untilArrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, untilArrayList);
    itemsListView = (ListView)findViewById(R.id.itemsListView);
    actionEditText = (EditText)findViewById(R.id.actionEditText);

    ////////////////////////////////////////////////////////////////////////////////

    arrayList.add("Monday");
    arrayList.add("Tuesday");
    arrayList.add("Wednesday");
    arrayList.add("Thursday");
    arrayList.add("Friday");
    arrayList.add("Saturday");
    arrayList.add("Sunday");
    final GlobalClass globalClass = (GlobalClass) this.getApplicationContext();
    dayListView.setAdapter(arrayAdapter);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
    dayListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, final int position, long id) {
            TextView enterActionTextView = (TextView)findViewById(R.id.enterActionTextView);
            EditText actionEditText = (EditText)findViewById(R.id.actionEditText);
            currentDay = arrayList.get(position);
            TextView enterTimeTextView = (TextView)findViewById(R.id.enterActionTextView);
            dayTextView.setText(currentDay);
            submitButton = (Button)findViewById(R.id.submitButton);
            submitButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    final String fromText = fromEditText.getText().toString();
                    final String untilText = untilEditText.getText().toString();
                    final String actionText = multiLineEditText.getText().toString();

                    if(fromText.matches("") || untilText.matches("") || actionText.matches("")){
                        Toast.makeText(getApplicationContext(), "Please fill the whole Form", Toast.LENGTH_LONG).show();
                    }else{                                                     
                        Toast.makeText(TimeForm.this, "Saved", Toast.LENGTH_SHORT).show();
                        globalClass.setTestString(actionText);
                        fromEditText.setText("");
                        untilEditText.setText("");
                        multiLineEditText.setText("");
                    }
                }
            });
        }
    });



}

@Override
public boolean onCreateOptionsMenu(Menu menu){
    getMenuInflater().inflate(R.menu.nevigation_menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    Intent reportBugIntent = new Intent(TimeForm.this, com.anastasispap.schedulemaker.ReportBug.class);
    Intent mainActivityIntent = new Intent(TimeForm.this, MainActivity.class);
    switch (item.getItemId()){
        case R.id.action_file:
            startActivity(timeFormIntent);
    }
    if(item.getItemId() == R.id.action_reportbug){
        startActivity(reportBugIntent);
    }else if(item.getItemId() == R.id.action_home){
        startActivity(mainActivityIntent);
   }

    return super.onOptionsItemSelected(item);

}

}

我要获取的字符串是fromText，toilText和actionText。我希望这些字符串在MainActivity中获得它们。

public class MainActivity extends AppCompatActivity {

private static final String TAG = "MainActivity";


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

    ListView itemsListView = (ListView) findViewById(R.id.itemsListView);
    final TextView itemsTextView = (TextView)findViewById(R.id.itemsTextView);
    final ArrayList<String> itemsArrayList = new ArrayList<String>();
    final TextView dayTextView = (TextView)findViewById(R.id.dayTextView);
    ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, itemsArrayList);

    Date currentTime = Calendar.getInstance().getTime();
    dayTextView.setText(new SimpleDateFormat("EEEE MM yyyy", Locale.ENGLISH).format(currentTime.getTime()));

    Button button = (Button)findViewById(R.id.button2);
    final GlobalClass globalClass = (GlobalClass) this.getApplicationContext();
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Toast.makeText(MainActivity.this, globalClass.getTestString(), Toast.LENGTH_SHORT).show();
        }
    });

}

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

    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    Intent timeFormIntent = new Intent(MainActivity.this, TimeForm.class);
    Intent reportBugIntent = new Intent(MainActivity.this, ReportBug.class);
    Intent mainActivityIntent = new Intent(MainActivity.this, MainActivity.class);
    switch (item.getItemId()){
        case R.id.action_file:
            startActivity(timeFormIntent);
    }
    if(item.getItemId() == R.id.action_reportbug){
        startActivity(reportBugIntent);
    }
    return super.onOptionsItemSelected(item);
}


}

Answer 1

您可以尝试为包含字符串的主要活动创建接口。

public interface IMainActivity {
void fromText(String fromText);
void untilText(String untilText);
void actionText(String actionText);
}

然后将实现的实例传递到TimeForm中（在这里Dagger会很好）。

Answer 2

您可以使用全局类来存储字符串。并在任何地方和您的代码中使用该字符串。您可以使用getter和setter来访问它。

public class GlobalClass extends Application {
    private String yourString;

    public String getYourString() {
        return yourString;
    }

    public void setYourString(String yourString) {
        this.yourString = yourString;
    }
}

在清单文件的应用程序标记中定义

<application
    android:name=".GlobalClass"

并在您使用的活动的onCreate功能中像这样使用它。

globalClass = (GlobalClass) this.getApplicationContext();

如果不是活动，（使用参数传递活动的上下文）

globalClass = (GlobalClass) context.getApplicationContext();

然后，您可以使用getter和setter来访问您的字符串。设置值，

String fromString = "some value";
globalClass.setYourString(fromString)

获取值

String fromString = globalClass.getYourString();

您可以使用此GlobalClass存储所有字符串以及您需要从多个activities和classes访问的所有其他值

如何从OnItemSelectedListener内的OnClickListener内的另一个类获取字符串

2 个答案: