Activity的生命周期

activity生命周期.png

关于Activity活动方法小实例

package com.example.activitylife;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private static final String TAG="ActivityLife";

    private Button btnstart;
    private TextView tvDispaly;

    private int count=0;
    private boolean mainFlag=false;
    private boolean isPause=true;

    private Handler handler =new Handler();
    @Override
    /**
     * onCreate做创建
     * 在Activity生命周期中onCreate只调用一次
     */
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Log.i("TAG","onCreate");
        //  启动线程
            new Thread(){
                public void run(){
                    mainFlag=true;
                    while (mainFlag){
                        if (!isPause) { //是否暂停
                            count++;
                            try {
                                Thread.sleep(1000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                            handler.post(new Runnable() {
                                @Override
                                public void run() {
                                    //运行在主线程中
                                    tvDispaly.setText(count + "");
                                }
                            });
                        }
                    }
                }
            }.start();
        btnstart=(Button)findViewById(R.id.btnstart);
        tvDispaly=(TextView)findViewById(R.id.tvDispaly);

        btnstart.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //使线程暂停及继续运行
                isPause=!isPause;
            }
        });
    }
    protected void onStart() {      //加载到内存，Activity不可见
        super.onStart();
        Log.i("TAG","onStart");
    }
    protected void onResume() {     //显示出来获得焦点，Activity可见
        super.onResume();
        Log.i("TAG","onResume");
        isPause=false;
    }
    protected void onPause() {      //暂停失去焦点，Activity可见
        super.onPause();
        Log.i("TAG","onPause");
        isPause=true;
    }
    protected void onStop() {       //停止，Activity不可见
        super.onStop();
        Log.i("TAG","onStop");
    }
    protected void onDestroy() {       //销毁，在Activity生命周期中onDestroy只调用一次
        super.onDestroy();
        mainFlag=false;
        Log.i("TAG","onDestroy");
    }
}