前面一定要先加入implements Runnable
public class MainActivity extends AppCompatActivity implements Runnable{
示範
XML<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="@+id/t1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="TextView"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
JAVA
public class MainActivity extends AppCompatActivity implements Runnable{
TextView t1;
private Handler handler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
t1=(TextView)findViewById(R.id.t1);
handler = new Handler() {
public void handleMessage(Message msg) {
t1.setText((String)msg.obj);
}
};
new Thread(this).start();
}
@Override
public void run() {
// TODO Auto-generated method stub
try {
while (true) {
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ssaa");//時間格式
String str = sdf.format(new Date());
handler.sendMessage(handler.obtainMessage(100, str));
Thread.sleep(1000);
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
展示
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