1.因为费时操作要放子线程，更新UI要放UI线程（主线程），所以子线程和主线程通信，通信的话要用到handler这个东西。
这里讲的比较简单，举2个例子说明
2.使用post的是handler ,使用message的是handler2
public class MainActivity extends AppCompatActivity {
private TextView textView;
private Handler handler = new Handler();
private Handler handler2=new Handler(){
@Override
public void handleMessage(Message msg) {
switch (msg.what){
case 1:
textView.setText(msg.obj.toString());
}
}
};
Button button;
private static final String TAG = "MainActivity";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView =findViewById(R.id.textview);
new Thread(){
@Override
public void run() {
Message message = new Message();
//区分标志
message.what=1;
//传参到ui线程
message.obj=123123;
handler2.sendMessage(message);
}
}.start();
new Thread(){
@Override
public void run() {
handler.post(new Runnable() {
@Override
public void run() {
textView.setText("fjidfjiijisdf");
}
});
}
}.start();
}
}
3. 实例化handler在其他线程的时候要下面这样写
private Handler handler = new Handler(Looper.getMainLooper());
