视图切换(ViewSwitcher)使用

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目录

ViewSwitcher

ViewSwitcher顾名思义. ViewSwitcher主要应用场景之一：比如在一个布局文件中，根据业务需求，需要在两个View间切换，在任意一个时刻，只能显示一个View.

ViewSwitcher本身继承了 FrameLayout,因此可以将多个View 层叠在一起，每次只显示一个组件。当程序控制从一个View切换到另一个View时， ViewSwitcher支持指定动画效果。

值得注意的是ViewSwitcher最多只能有2个view.
ViewSwitcher的addView函数的代码如下：

/**
 * {@inheritDoc}
 *
 * @throws IllegalStateException if this switcher already contains two children
 */
@Override
public void addView(View child, int index, ViewGroup.LayoutParams params) {
  if (getChildCount() >= 2) {
    throw new IllegalStateException("Can't add more than 2 views to a ViewSwitcher");
  }
  super.addView(child, index, params);
}

当view超过2时,就会报错.

使用:

    <ViewSwitcher
        android:id="@+id/viewswitcher"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="251dp"
        android:layout_marginBottom="145dp" >

        <ImageView
            android:layout_width="400dp"
            android:layout_height="400dp"
            android:src="@drawable/p001" />

        <ImageView
            android:layout_width="400dp"
            android:layout_height="400dp"
            android:src="@drawable/p002" />

    </ViewSwitcher>

使用实例

activity_main.xml文件:

<?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">

    <LinearLayout
        android:id="@+id/linearLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/prev"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="previous" />

        <Button
            android:id="@+id/next"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="next" />
    </LinearLayout>

    <ViewSwitcher
        android:id="@+id/viewswitcher"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="251dp"
        android:layout_marginBottom="145dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/linearLayout">

        <ImageView
            android:layout_width="400dp"
            android:layout_height="400dp"
            android:src="@drawable/p001" />

        <ImageView
            android:layout_width="400dp"
            android:layout_height="400dp"
            android:src="@drawable/p002" />

    </ViewSwitcher>

</android.support.constraint.ConstraintLayout>

代码实现:

package com.example.user.viewsw;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ViewSwitcher;

public class MainActivity extends AppCompatActivity {
    Button buttonPrev, buttonNext;
    ViewSwitcher viewSwitcher;
    Animation slide_in_left, slide_out_right;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // 获取按钮
        buttonPrev = (Button) findViewById(R.id.prev);
        buttonNext = (Button) findViewById(R.id.next);

        // 获取ViewSwitcher
        viewSwitcher = (ViewSwitcher) findViewById(R.id.viewswitcher);

        // 载入动画效果
        slide_in_left = AnimationUtils.loadAnimation(this,
                android.R.anim.slide_in_left);
        slide_out_right = AnimationUtils.loadAnimation(this,
                android.R.anim.slide_out_right);

        // 设定动画效果
        viewSwitcher.setInAnimation(slide_in_left);
        viewSwitcher.setOutAnimation(slide_out_right);

        buttonPrev.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                viewSwitcher.showPrevious();
            }
        });

        buttonNext.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                viewSwitcher.showNext();
            }
        });
    }
}

运行效果:

image.png
image.png

参考

Android零基础入门第54节：视图切换组件ViewSwitcher
android使用ViewSwitcher实现视图切换