刷新活动使用onResume（） [英] Refresh Activity using onResume()

问题描述

我有一个手电筒活动。通常它工作正常，但如果我去其他任何活动，它停止工作！

所以我想刷新code，当我回到手电筒活动。

我认为使用刷新 onResume（）将帮助我最好的，但是怎么办呢？

 公共类FlashLightActivity延伸活动{//标志检测闪光灯开启或关闭
私人布尔isLighOn = FALSE;私人相机拍照;私人按钮NEXT1，​​NEXT2;@覆盖
保护无效的onStop（）{
    super.onStop（）;    如果（相机！= NULL）{
        camera.release（）;
    }
}@覆盖
公共无效的onCreate（捆绑savedInstanceState）{
    super.onCreate（savedInstanceState）;
    的setContentView（R.layout.main）;
        NEXT1 =（按钮）findViewById（R.id.ebtn28_answer）;
        next1.setOnClickListener（新View.OnClickListener（）{
            公共无效的onClick（查看视图）{
                意图myIntent =新意图（view.getContext（），FullScreen.class）;
                startActivityForResult（myIntent，0）;
            }        }）;    NEXT2 =（按钮）findViewById（R.id.buttonFlashlight）;    上下文的背景下=这;
    软件包管理系统下午= context.getPackageManager（）;    //如果设备支持相机？
    如果（！pm.hasSystemFeature（PackageManager.FEATURE_CAMERA））{
        Log.e（犯错，设备没有摄像头！）;
        返回;
    }    相机= Camera.open（）;
    最终的参数P = camera.getParameters（）;    next2.setOnClickListener（新OnClickListener（）{        @覆盖
        公共无效的onClick（查看为arg0）{            如果（isLighOn）{                Log.i（信息，火炬被关闭！）;                p.setFlashMode（Parameters.FLASH_MODE_OFF）;
                camera.setParameters（P）;
                camera.stop preVIEW（）;
                isLighOn = FALSE;            }其他{                Log.i（信息，火炬被打开！）;                p.setFlashMode（Parameters.FLASH_MODE_TORCH）;                camera.setParameters（P）;
                camera.start preVIEW（）;
                isLighOn =真;            }        }
    }）;}
  }
 

解决方案

您需要覆盖的onPause和onResume。在的onPause，你需要释放相机。在onResume，您需要重新提出要求。如果您尝试持有它的时候你是不是活泼的活动相机不喜欢它。

 公共无效的onPause（）{
    super.onPause（）;
    如果（相机！= NULL）{
        camera.release（）;
        摄像头= NULL;
    }
}公共无效onResume（）{
    super.onResume（）;
    //需要释放，如果我们已经有一个，否则我们不会拿相机
    如果（相机！= NULL）{
        camera.release（）;
        摄像头= NULL;
    }
    尝试{
        相机= Camera.open（）;
    }
    赶上（例外五）{
    }}
 

I have a Flashlight Activity. Normally it works fine but When I go to any other activity, it stop working!

So I want to refresh the code when I back to the Flashlight Activity.

I think refreshing using onResume() would help me best, But how to do it?

public class FlashLightActivity extends Activity {

//flag to detect flash is on or off
private boolean isLighOn = false;

private Camera camera;

private Button next1, next2;

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

    if (camera != null) {
        camera.release();
    }
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


        next1 = (Button) findViewById(R.id.ebtn28_answer);
        next1.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                Intent myIntent = new Intent(view.getContext(), FullScreen.class);
                startActivityForResult(myIntent, 0);
            }

        });

    next2 = (Button) findViewById(R.id.buttonFlashlight);

    Context context = this;
    PackageManager pm = context.getPackageManager();

    // if device support camera?
    if (!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
        Log.e("err", "Device has no camera!");
        return;
    }

    camera = Camera.open();
    final Parameters p = camera.getParameters();

    next2.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {

            if (isLighOn) {

                Log.i("info", "torch is turn off!");

                p.setFlashMode(Parameters.FLASH_MODE_OFF);
                camera.setParameters(p);
                camera.stopPreview();
                isLighOn = false;

            } else {

                Log.i("info", "torch is turn on!");

                p.setFlashMode(Parameters.FLASH_MODE_TORCH);

                camera.setParameters(p);
                camera.startPreview();
                isLighOn = true;

            }

        }
    });

}
  }                                                              

解决方案

You need to override onPause and onResume. In onPause, you need to release the Camera. In onResume, you need to re-request it. Camera doesn't like it if you try to hold it when you aren't the active activity.

public void onPause(){
    super.onPause();
    if(camera != null){
        camera.release();
        camera = null;
    }
}

public void onResume(){
    super.onResume();
    //Need to release if we already have one, or we won't get the camera
    if(camera != null){
        camera.release();
        camera = null;          
    }
    try {
        camera = Camera.open(); 
    }
    catch (Exception e){
    }

}

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