子執行緒向主執行緒傳遞訊息
阿新 • • 發佈：2019-02-07
package com.example.day19_handler_demo1;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.widget.TextView;
public class MainActivity extends Activity {
private TextView tv;
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- 案例二 Message幾個資訊載體:
package com.qf.day19_handler_demo2;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
public class MainActivity extends Activity {
private Handler handler = new Handler(){
public void handleMessage(android.os.Message msg) {
//接收和處理訊息的
switch (msg.what) {//根據標記進行處理資料
case 1:
int a = msg.arg1;
int a2 = msg.arg2;
String str = (String) msg.obj;
int flag = msg.what;
Log.e("AAA", "==a=="+a);
Log.e("AAA", "==a2=="+a2);
Log.e("AAA", "==str=="+str);
Log.e("AAA", "==flag=="+flag);
break;
case 2:
Log.e("AAAA", "AAAAAAAAAAAAAAAA");
break;
default:
break;
}
};
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
//子執行緒裡的資料傳送到主執行緒
public void OnMyClick(View v){
new Thread(){
public void run() {
//獲取訊息的載體物件
Message msg = Message.obtain();
msg.arg1 = 100;
msg.arg2 = 200;//arg1,arg2:都是int型別資料
msg.obj = "我是大資料"; //Object物件 string Bitmap List<T>
msg.what = 1;//int 型別 標記
handler.sendMessage(msg);
};
}.start();
}
}
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- 案例三 幾個傳送msg的方式:
package com.qf.day19_handler_demo4;
import android.app.Activity;
import android.app.ProgressDialog;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
public class MainActivity extends Activity {
private ImageView ivShow;
Handler handler = new Handler();
Handler handler2 = new Handler(){
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case 1:
pDialog.show();
break;
case 2:
Bitmap bitmap = (Bitmap) msg.obj;
ivShow.setImageBitmap(bitmap);
pDialog.dismiss();
break;
default:
break;
}
};
};
private ProgressDialog pDialog;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ivShow = (ImageView) findViewById(R.id.iv_show);
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setTitle("下載圖片");
pDialog.setIcon(R.drawable.ic_launcher);
pDialog.setMessage("正在下載中,請稍後...");
}
public void MyLoadClick(View v) {
//pDialog.show();
//開啟子執行緒下載圖片
new Thread(){
public void run() {
//在子執行緒展示
//傳送null訊息 只設置一個標記
handler2.sendEmptyMessage(1);
byte[] data = HttpUtil.getHttpResult("https://ss2.baidu.com/6ONYsjip0QIZ8tyhnq/it/u=2507878052,3446525205&fm=58");
final Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
//第一種方式 將程式碼塊傳送到主執行緒 在內部直接一個匿名內部類runnable 可以直接更新UI（主執行緒）
// handler.post(new Runnable() {
//
// @Override
// public void run() {
// // TODO Auto-generated method stub
// Log.e("AAA", "=handler=>"+Thread.currentThread().getName());
//
// //更新Ui
// ivShow.setImageBitmap(bitmap);
// pDialog.dismiss();
// }
// });
//延遲傳送 在內部直接一個匿名內部類runnable 可以直接更新UI（主執行緒）
// handler.postDelayed(r, delayMillis)
//第二種方式 使用msg 攜帶資料到主執行緒
// Message msg = Message.obtain();
// msg.obj = bitmap;
// msg.what = 2;
// handler2.sendMessage(msg);
// 延遲傳送一個msg
//handler2.sendMessageDelayed(msg, delayMillis)
//第三種 sendToTarget 傳送到那個Handler
// Message msg = handler2.obtainMessage();
// msg.obj = bitmap;
// msg.what = 2;
// msg.sendToTarget();//傳送給那個Handler
//第四種方式
Message msg = Message.obtain();
msg.obj = bitmap;
msg.what = 2;
msg.setTarget(handler2);//指明是那個Handler
msg.sendToTarget();//傳送給那個Handler
};
}.start();
}
}