android USES include to invoke methods on internal components
- 2020-06-19 11:44:00
- OfStack
This article shows how android USES include to invoke internal components. Share to everybody for everybody reference. The details are as follows:
Example 1:
sublayout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#505050"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="SubLayout"
/>
<Button
android:id="@+id/mybutton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text=" A Button "
/>
</LinearLayout>
mail.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<include android:id="@+id/main1" layout="@layout/sublayout" />
<include android:id="@+id/main2" layout="@layout/sublayout" />
<Button
android:id="@+id/startanotheractivity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=" Start Another Activity "
/>
</LinearLayout>
How do you call components that come in from component include?
package com.AndroidIncludeLayout;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class AndroidIncludeLayout extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
View subLayout1 = (View)findViewById(R.id.main1);
View subLayout2 = (View)findViewById(R.id.main2);
Button myButton_main1 = (Button)subLayout1.findViewById(R.id.mybutton);
Button myButton_main2 = (Button)subLayout2.findViewById(R.id.mybutton);
Button startAnotherActivity = (Button)findViewById(R.id.startanotheractivity);
startAnotherActivity.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent intent = new Intent();
intent.setClass(AndroidIncludeLayout.this, AnotherActivity.class);
startActivity(intent);
}});
myButton_main1.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Toast.makeText(AndroidIncludeLayout.this, "Button 1 Pressed", Toast.LENGTH_LONG).show();
}});
myButton_main2.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Toast.makeText(AndroidIncludeLayout.this, "Button 2 Pressed", Toast.LENGTH_LONG).show();
}});
}
}
But if include comes in xml, yes
sublayout.xml
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="SubLayout"
/>
<Button
android:id="@+id/mybutton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text=" A Button "
/>
</merge>
The above method will not be implemented, will report null pointer.
Because with merge, importing is equivalent to the current component under view, you can just go straight to findViewById.
In that case... The problem of the same include multiple times can be solved
Hopefully, this article has helped you with your Android programming.