Question

嗨，我正在寻找手电筒应用程序源代码，我修改了一点点当我最小化应用程序手电筒将关闭所以我只使用onDestroy（）方法关闭应用程序状态但是当我关闭时，有时应用程序甚至不工作它显示闪光灯但不打开闪光灯这就是我做的事情

public class MainActivity extends AppCompatActivity {

Button button;
private Camera camera;
private boolean isFlashOn;
private boolean hasFlash;
Parameters params;




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

   final ImageButton imgbutton = (ImageButton)findViewById(R.id.imageButton);





    hasFlash = getApplicationContext().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);



    getCamera();

    //button.setOnClickListener(new View.OnClickListener() {
         imgbutton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            if (isFlashOn) {
                turnOffFlash();

                Toast.makeText(MainActivity.this, "Flash OFF!", Toast.LENGTH_SHORT).show();
                imgbutton.setImageResource(R.drawable.light_off);

            } else {
                turnOnFlash();

                Toast.makeText(MainActivity.this, "Flash ON!", Toast.LENGTH_SHORT).show();
                imgbutton.setImageResource(R.drawable.light_on);
            }

        }
    });
}

private void getCamera() {

    if (camera == null) {
        try {
            camera = Camera.open();
            params = camera.getParameters();
        }catch (Exception e) {

        }
    }

}

private void turnOnFlash() {

    if(!isFlashOn) {
        if(camera == null || params == null) {
            return;
        }

        params = camera.getParameters();
        params.setFlashMode(Parameters.FLASH_MODE_TORCH);
        camera.setParameters(params);
        camera.startPreview();
        isFlashOn = true;
    }

}

private void turnOffFlash() {

    if (isFlashOn) {
        if (camera == null || params == null) {
            return;
        }

        params = camera.getParameters();
        params.setFlashMode(Parameters.FLASH_MODE_OFF);
        camera.setParameters(params);
        camera.stopPreview();
        isFlashOn = false;
    }
}

protected void onDestroy(){

    if(camera!=null){

        camera.stopPreview();
        camera.setPreviewCallback(null);

        camera.release();
        camera = null;
    }


} }

Answer 1

你忘了覆盖：

onStop()

@Override
  protected void onStop() {
      super.onStop();
      if (camera != null) {
          camera.release();
          camera = null;
      }
  }

onResume()

@Override
  protected void onResume() {
      super.onResume();
      if(hasFlash)
          turnOnFlash();
  }

获取hasFlash我建议您将其放入onCreate()以了解设备是否有闪存

hasFlash = getApplicationContext().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);

onPause()

@Override
  protected void onPause() {
      super.onPause();
      turnOffFlash();
  }

顺便说一下，你重复了代码......

Answer 2

使用onPause()和onResume()方法并在此处执行您的代码。

@Override
    protected void onPause() {
        super.onPause();

       //Your code
    }

@Override
    protected void onResume() {
        super.onResume();

//Your code
    }

闪光灯不会打开/相机错误

2 个答案: