Activity-生命周期

Activity--生命周期

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class FirstActivity extends Activity {
    
    private static final String LOG_TAG="VERBOSE";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button b = (Button) findViewById(R.id.start);
        b.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(FirstActivity.this, SecondActivity.class);
                startActivity(intent);
            }
        });
        Log.v(LOG_TAG, "FirstActivity:onCreate");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.v(LOG_TAG, "FirstActivity:onDestroy");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.v(LOG_TAG, "FirstActivity:onPause");
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.v(LOG_TAG, "FirstActivity:onResume");
    }
    
    @Override
    protected void onRestart() {
        super.onRestart();
        Log.v(LOG_TAG, "FirstActivity:onRestart");
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.v(LOG_TAG, "FirstActivity:onStart");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.v(LOG_TAG, "FirstActivity:onStop");
    }
    
}

 

 

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class SecondActivity extends Activity {
    
    private static final String LOG_TAG="VERBOSE";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second);
        Button b = (Button) findViewById(R.id.back);
        b.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                finish();
            }
        });
        Button s = (Button) findViewById(R.id.start3);
        s.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(SecondActivity.this, ThirdActivity.class);
                startActivity(intent);
            }
        });
        Log.v(LOG_TAG, "SecondActivity:onCreate");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.v(LOG_TAG, "SecondActivity:onDestroy");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.v(LOG_TAG, "SecondActivity:onPause");
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        Log.v(LOG_TAG, "SecondActivity:onRestart");
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.v(LOG_TAG, "SecondActivity:onResume");
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.v(LOG_TAG, "SecondActivity:onStart");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.v(LOG_TAG, "SecondActivity:onStop");
    }
}

 

 

1.启动该程序，输出：

FirstActivity:onCreate

FirstActivity:onStart
FirstActivity:onResume

 

2.点击Start SecondActivity，输出：

FirstActivity:onPause

SecondActivity:onCreate

SecondActivity:onStart

SecondActivity:onResume

FirstActivity:onStop

 

3.点击Back to FirstActivity或者按BACK key，输出：

SecondActivity:onPause

FirstActivity:onRestart

FirstActivity:onStart

FirstActivity:onResume

SecondActivity:onStop

SecondActivity:onDestroy