android Activity生命周期的事例

package com.example.yanlei.yl2;import android.app.AlertDialog;import android.content.DialogInterface;import android.content.DialogInterface.OnKeyListener;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.app.Activity;import android.os.Bundle;import android.util.Log;import android.widget.TextView;public class MainActivity extends AppCompatActivity {    public static final String TAG = "生命周期:";    String Str = "";    TextView pTextView = null;    @Override    public void onCreate(Bundle savedInstanceState) {        //当创建此Activity的时候回调        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        Log.e(TAG, "onCreate");        try {            Str = Str + "创建：\n";            pTextView.setText(Str);        } catch (Exception e) {            //Log.e(TAG, "error : "+e.getMessage(), e);        }    }    @Override    protected void onDestroy() {        //当销毁此Activity的时候回调        super.onDestroy();        Log.e(TAG, "onDestroy");        try {            Str = Str + "摧毁：\n";            pTextView.setText(Str);        } catch (Exception e) {            //Log.e(TAG, "error : "+e.getMessage(), e);        }    }    @Override    protected void onPause() {        //当暂停此Activity的时候回调        super.onPause();        Log.e(TAG, "onPause");        try {            Str = Str + "暂停：\n";            pTextView.setText(Str);        } catch (Exception e) {            // Log.e(TAG, "error : "+e.getMessage(), e);        }    }    @Override    protected void onRestart() {        //当重新开始此Activity的时候回调        super.onRestart();        Log.e(TAG, "onRestart");        try        {            Str = Str + "重新启动：\n";            pTextView.setText(Str);        } catch (Exception e) {            //Log.e(TAG, "error : "+e.getMessage(), e);        }    }    @Override    protected void onResume() {        //当显示展示此Activity的界面的时候回调        super.onResume();        Log.e(TAG, "onResume");        try {            Str = Str + "继续：\n";            pTextView.setText(Str);        } catch (Exception e) {            //Log.e(TAG, "error : "+e.getMessage(), e);        }    }    @Override    protected void onStart() {        //当使用此Activity可以接受用户操作的时候回调        super.onStart();        Log.e(TAG, "onStart");        try {            Str = Str + "开始：\n";            pTextView.setText(Str);        } catch (Exception e) {            //Log.e(TAG, "error : "+e.getMessage(), e);        }    }    @Override    protected void onStop() {        //当停止此Activity的时候回调        super.onStop();        Log.e(TAG, "onStop");        try {            Str = Str + "停止：\n";            pTextView.setText(Str);        } catch (Exception e) {            //Log.e(TAG, "error : "+e.getMessage(), e);        }    }}