Android Activity的生命周期与启动模式全面解读

package com.qingsu.yingguday06;

import androidx.appcompat.app.AppCompatActivity;

import android.content.ComponentName;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private  Button mBtIntent,mBtIntentOne,mBtIntentTwo,mBtIntentThree;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Log.d("TAG","onCreate");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        mBtIntent.setOnClickListener(this);
    }


    private  void initView(){
        mBtIntent = findViewById(R.id.bt_intentmain);
    }
    @Override
    protected void onStart() {
        Log.d("TAG","onStart");
        super.onStart();
    }

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

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

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

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

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

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.bt_intentmain:
                startActivity(intent);;
                break;
            default:
                break;
        }
    }

    
}

package com.qingsu.yingguday06;

import androidx.appcompat.app.AppCompatActivity;

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

public class HomeActivity extends AppCompatActivity {

    Button mBtHome,mBtIntentB;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d("TAG","BonCreate");
        setContentView(R.layout.activity_home);
        setTitle("页面B");
        mBtHome = findViewById(R.id.bt_intenthome);
        mBtIntentB = findViewById(R.id.bt_intentB);
        mBtHome.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(HomeActivity.this,MainActivity.class);
                startActivity(intent);
            }
        });
        mBtIntentB.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(HomeActivity.this,HomeActivity.class);
                startActivity(intent);
            }
        });
    }
    @Override
    protected void onStart() {
        Log.d("TAG","BonStart");
        super.onStart();
    }

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

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

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

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

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

}

 android:launchMode="singleTask"

     <activity android:name=".MainActivity"
            android:launchMode="singleTask"
            >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>