Android組件ViewStub基本使用方法詳解

2019-12-12 06:17:48

字體：大中小

供稿：網(wǎng)友

ViewStub可以在運行時動態(tài)的添加布局。幫助文檔給定的定義是：

"A ViewStub is an invisible, zero-sized View that can be used to lazily inflate layout resources at runtime. When a ViewStub is made visible, or when inflate() is invoked, the layout resource is inflated. The ViewStub then replaces itself in its parent with the inflated View or Views. Therefore, the ViewStub exists in the view hierarchy until setVisibility(int) or inflate() is invoked. The inflated View is added to the ViewStub's parent with the ViewStub's layout parameters. Similarly, you can define/override the inflate View's id by using the ViewStub's inflatedId property.”

總之是：ViewStub可以給其他的view事先占據(jù)好位置，當(dāng)需要的時候調(diào)用inflater()或者是setVisible（）方法顯示這些View組件。

layout.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:tools="http://schemas.android.com/tools"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:orientation="vertical"  tools:context=".MainActivity" >  <LinearLayout    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:orientation="horizontal" >    <Button      android:id="@+id/showBtn"      android:layout_width="match_parent"      android:layout_height="50dip"      android:layout_weight="1"      android:text="show" />    <Button      android:id="@+id/deleteBtn"      android:layout_width="match_parent"      android:layout_height="50dip"      android:layout_weight="1"      android:text="delete" />  </LinearLayout>  <LinearLayout    android:layout_width="wrap_content"    android:layout_height="wrap_content" >    <ViewStub      android:id="@+id/viewstub"      android:layout_width="wrap_content"      android:layout_height="wrap_content"      android:layout="@layout/next" />      </LinearLayout></LinearLayout>

next.xml:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:orientation="vertical" >  <ProgressBar    android:id="@+id/progressBar1"    style="?android:attr/progressBarStyleLarge"    android:layout_width="wrap_content"    android:layout_height="wrap_content" /></LinearLayout>

Main.java:

package com.example.android_viewstub1;import android.os.Bundle;import android.annotation.SuppressLint;import android.app.Activity;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.view.ViewStub;import android.widget.Button;public class MainActivity extends Activity {  Button btn1, btn2;  ViewStub viewStub;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    btn1 = (Button) this.findViewById(R.id.showBtn);    btn2 = (Button) this.findViewById(R.id.deleteBtn);    viewStub = (ViewStub) this.findViewById(R.id.viewstub);    btn1.setOnClickListener(new OnClickListener() {      @SuppressLint("NewApi")      @Override      public void onClick(View arg0) {        viewStub.setVisibility(View.VISIBLE);      }    });    btn2.setOnClickListener(new OnClickListener() {      @SuppressLint("NewApi")      @Override      public void onClick(View arg0) {        viewStub.setVisibility(View.INVISIBLE);      }    });  }}

效果：