从其他活动返回后，OnClickListener停止工作

Question

For some reason when I call startActivityForResult within a button listener, and return from the activity, all the buttons stop working thereafter. It goes through and exits onActivityResult just fine, and the app doesn't freeze since I can still click on the buttons although they don't do anything. When starting the app it works as it should. What am I missing here?

public class MainActivity extends Activity {

    static final int CAMERA_RESULT_CODE = 1;
    static final int INFO_RESULT_CODE = 2;
    static final int SYMPTOM_RESULT_CODE = 3;

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

        // Set the user interface elements
        final Button btnCameraActivity = (Button) findViewById(R.id.btnCameraActivity);
        btnCameraActivity.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, CropActivity.class);
                startActivityForResult(intent, CAMERA_RESULT_CODE);
            }
        });

        final Button btnAgeActivity = (Button) findViewById(R.id.btnAgeActivity);
        btnAgeActivity.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, AgeActivity.class);
                startActivityForResult(intent, INFO_RESULT_CODE);
            }
        });

        final Button btnSymptomActivity = (Button) findViewById(R.id.btnSymptomActivity);
        btnSymptomActivity.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, SymptomActivity.class);
                startActivityForResult(intent, SYMPTOM_RESULT_CODE);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        setContentView(R.layout.activity_main);
        switch (requestCode) {
            case CAMERA_RESULT_CODE:
                if (resultCode == RESULT_OK) {
                    final CheckBox cb1 = (CheckBox) findViewById(R.id.cbCameraActivity);
                    cb1.setChecked(true);
                }
                break;
            case INFO_RESULT_CODE:
                if (resultCode == RESULT_OK) {
                    final CheckBox cb2 = (CheckBox) findViewById(R.id.cbAgeActivity);
                    cb2.setChecked(true);
                }
                break;
            case SYMPTOM_RESULT_CODE:
                if (resultCode == RESULT_OK) {
                    final CheckBox cb3 = (CheckBox) findViewById(R.id.cbSymptomActivity);
                    cb3.setChecked(true);
                }
                break;
        }
    }
}

Answer 1

The setContentView() call you have in onActivityResult() is replacing the layout you've setup in onCreate() , so those Button instances that you set the OnClickListener s on are gone.

Simply remove that call from the top of onActivityResult() .

Answer 2

put this code in onResume method

    final Button btnCameraActivity = (Button) findViewById(R.id.btnCameraActivity);
    btnCameraActivity.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(MainActivity.this, CropActivity.class);
            startActivityForResult(intent, CAMERA_RESULT_CODE);
        }
    });

    final Button btnAgeActivity = (Button) findViewById(R.id.btnAgeActivity);
    btnAgeActivity.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            Intent intent = new Intent(MainActivity.this, AgeActivity.class);
            startActivityForResult(intent, INFO_RESULT_CODE);
        }
    });

    final Button btnSymptomActivity = (Button) findViewById(R.id.btnSymptomActivity);
    btnSymptomActivity.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(MainActivity.this, SymptomActivity.class);
            startActivityForResult(intent, SYMPTOM_RESULT_CODE);
        }
    });

also this code can be generally simplified by extending youre class to View.OnClickListener