- 案例一 Message创建三种方法:
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;
private int count =0;
private Handler handler = new Handler(){
public void handleMessage(android.os.Message msg) {
Log.e("AAA", "=handleMessage=>"+Thread.currentThread().getName());
//处理消息
//获取消息
int num = msg.arg1;
//更新数据
tv.setText(num+"");
};
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView) findViewById(R.id.tv);
// android.view.ViewRootImpl$CalledFromWrongThreadException:
// Only the original thread that created a view hierarchy
// can touch its views.
new Thread(){
public void run() {
while(true){
if(count<100){
count++;
}
Log.e("AAA", "=Thread=>"+Thread.currentThread().getName());
// tv.setText(count+"");
//方式一获取Message对象 不建议使用
//Message msg = new Message(); 如果用sendToTarget想要setTarget
//方式二获取Message对象
//Message msg = Message.obtain(); 方便后面用sendToTarget
//方式三获取Message对象
Message msg = handler.obtainMessage();
//msg携带数据
msg.arg1 = count;
//使用Handler发送数据
handler.sendMessage(msg);
try {
sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
}.start();
}
}
- 案例二 Message几个信息载体:
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) {
//接收和处理消息的
switch (msg.what) {//根据标记进行处理数据
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);
}
//子线程里的数据发送到主线程
public void OnMyClick(View v){
new Thread(){
public void run() {
//获取消息的载体对象
Message msg = Message.obtain();
msg.arg1 = 100;
msg.arg2 = 200;//arg1,arg2:都是int类型数据
msg.obj = "我是大数据"; //Object对象 string Bitmap List<T>
msg.what = 1;//int 类型 标记
handler.sendMessage(msg);
};
}.start();
}
}
- 案例三 几个发送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("下载图片");
pDialog.setIcon(R.drawable.ic_launcher);
pDialog.setMessage("正在下载中,请稍后...");
}
public void MyLoadClick(View v) {
//pDialog.show();
//开启子线程下载图片
new Thread(){
public void run() {
//在子线程展示
//发送null消息 只设置一个标记
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);
//第一种方式 将代码块发送到主线程 在内部直接一个匿名内部类runnable 可以直接更新UI（主线程）
// 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();
// }
// });
//延迟发送 在内部直接一个匿名内部类runnable 可以直接更新UI（主线程）
// handler.postDelayed(r, delayMillis)
//第二种方式 使用msg 携带数据到主线程
// Message msg = Message.obtain();
// msg.obj = bitmap;
// msg.what = 2;
// handler2.sendMessage(msg);
// 延迟发送一个msg
//handler2.sendMessageDelayed(msg, delayMillis)
//第三种 sendToTarget 发送到那个Handler
// Message msg = handler2.obtainMessage();
// msg.obj = bitmap;
// msg.what = 2;
// msg.sendToTarget();//发送给那个Handler
//第四种方式
Message msg = Message.obtain();
msg.obj = bitmap;
msg.what = 2;
msg.setTarget(handler2);//指明是那个Handler
msg.sendToTarget();//发送给那个Handler
};
}.start();
}
}