从我的线程执行时，Acitivity 会忽略显示 Toast
为什么我只看到“第一个”toast，而看不到从我的线程创建的其他（应该）toast？
public class BannerExample extends Activity {
@Override
public void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Toast toast = Toast.makeText(this, "first toast", Toast.LENGTH_SHORT);
toast.show();
new MyThread(this).start();
}
class MyThread extends Thread {
private Context context;
public MyThread(Context context) {
this.context = context;
}
public void run() {
Looper.prepare(); // An exception told me to add this - i have no clue why
for (int i = 0; i < 3; i++) {
try {
sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Toast toast = Toast.makeText(context, i + "whoho", Toast.LENGTH_SHORT);
toast.show();
}
}
}
}
Why do I only see the "first" toast and not the others (should be) created from my thread?
public class BannerExample extends Activity {
@Override
public void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Toast toast = Toast.makeText(this, "first toast", Toast.LENGTH_SHORT);
toast.show();
new MyThread(this).start();
}
class MyThread extends Thread {
private Context context;
public MyThread(Context context) {
this.context = context;
}
public void run() {
Looper.prepare(); // An exception told me to add this - i have no clue why
for (int i = 0; i < 3; i++) {
try {
sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Toast toast = Toast.makeText(context, i + "whoho", Toast.LENGTH_SHORT);
toast.show();
}
}
}
}
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Looper.prepare。您收到异常是因为您做错了什么：Thread对于AsyncTask并利用 < code>onProgressUpdate 方法来创建 Toast，因为它会自动在 UI 线程上运行。否则，您将需要使用处理程序。getBaseContext传递到构造函数，而不是从当前活动的上下文Looper.prepare. You were getting the exception because you were doing something wrong:ThreadforAsyncTaskand make use of theonProgressUpdatemethod to create your toasts as this automatically runs on the UI thread. Otherwise you'll need to use a handler.getBaseContextrather than the context from the current activity to your constructor