XMl:
<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"
android:orientation="vertical"
tools:context="com.example.a123.myapplication1.MainActivity">
<TextView
android:text="倒计时"
android:textSize="30dp"
android:gravity="center_horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/name"
android:text="5"
android:textSize="70dp"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>
Activity页面:
public class MainActivity extends AppCompatActivity {
private TextView name;
private Handler handler=new Handler();
private int a=5;
private Runnable runnable=new Runnable() {
@Override
public void run() {
a--;
name.setText(a+"");
if (a==0){
Intent intent=new Intent(MainActivity.this,JieXi.class);
startActivity(intent);
}else {
handler.postDelayed(runnable,1000);
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
private void initView() {
name = (TextView) findViewById(R.id.name);
handler.postDelayed(runnable,1000);
}
}
<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"
android:orientation="vertical"
tools:context="com.example.a123.myapplication1.MainActivity">
<TextView
android:text="倒计时"
android:textSize="30dp"
android:gravity="center_horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/name"
android:text="5"
android:textSize="70dp"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>
Activity页面:
public class MainActivity extends AppCompatActivity {
private TextView name;
private Handler handler=new Handler();
private int a=5;
private Runnable runnable=new Runnable() {
@Override
public void run() {
a--;
name.setText(a+"");
if (a==0){
Intent intent=new Intent(MainActivity.this,JieXi.class);
startActivity(intent);
}else {
handler.postDelayed(runnable,1000);
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
private void initView() {
name = (TextView) findViewById(R.id.name);
handler.postDelayed(runnable,1000);
}
}