first

activity的生命周期 ##核心代码

public class First_Activity extends AppCompatActivity {
    public static final String TAG="MainActivity";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d(TAG,"OnCreat");
        setContentView(R.layout.first_layout);
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.d(TAG,"OnStart");
    }

    @Override
    protected void onPostResume() {
        super.onPostResume();
        Log.d(TAG,"OnResume");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.d(TAG,"OnPause");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.d(TAG,"OnStop");
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        Log.d(TAG,"OnRestart");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d(TAG,"OnDestroy");
    }
}

运行截图

1.进入软件

2.home键退出

3.再进入软件

4.关闭软件