本文章主要介绍了Android控件之ImageView探究，具有不错的的参考价值，希望对您有所帮助，如解说有误或未考虑完全的地方，请您留言指出，谢谢！
ImageView控件是一个图片控件，负责显示图片。
以下模拟手机图片查看器
目录结构
main.xml布局文件
<? 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 " >
< ImageView android:id = " @+id/imageView "
android:layout_width = " wrap_content "
android:layout_height = " wrap_content "
android:layout_gravity = " center_horizontal "
android:src = " @drawable/p1 " />
< LinearLayout xmlns:android = " http://schemas.android.com/apk/res/android "
android:orientation = " horizontal "
android:layout_width = " fill_parent "
android:layout_height = " wrap_content "
android:layout_gravity = " center_horizontal " >
< Button android:id = " @+id/previous "
android:layout_width = " wrap_content "
android:layout_height = " wrap_content "
android:text = " 上一张 "
android:layout_gravity = " center_horizontal " />
< Button android:id = " @+id/alpha_plus "
android:layout_width = " wrap_content "
android:layout_height = " wrap_content "
android:text = " 透明度增加 "
android:layout_gravity = " center_horizontal " />
< Button android:id = " @+id/alpha_minus "
android:layout_width = " wrap_content "
android:layout_height = " wrap_content "
android:text = " 透明度减少 "
android:layout_gravity = " center_horizontal " />
< Button android:id = " @+id/next "
android:layout_width = " wrap_content "
android:layout_height = " wrap_content "
android:text = " 下一张 "
android:layout_gravity = " center_horizontal " />
</ LinearLayout >
</ LinearLayout >
ImageViewActivity类
package com.ljq.iv;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
public class ImageViewActivity extends Activity {
private ImageView imageView = null ;
private Button previous = null ; // 上一张
private Button next = null ; // 下一张
private Button alpha_plus = null ; // 透明度增加
private Button alpha_minus = null ; // 透明度减少
private int currentImgId = 0 ; // 记录当前ImageView显示的图片id
private int alpha = 255 ; // 记录ImageView的透明度
int [] imgId = { // ImageView显示的图片数组
R.drawable.p1,
R.drawable.p2,
R.drawable.p3,
R.drawable.p4,
R.drawable.p5,
R.drawable.p6,
R.drawable.p7,
R.drawable.p8,
};
@Override
public void onCreate(Bundle savedInstanceState) {
super .onCreate(savedInstanceState);
setContentView(R.layout.main);
imageView = (ImageView)findViewById(R.id.imageView);
previous = (Button)findViewById(R.id.previous);
next = (Button)findViewById(R.id.next);
alpha_plus = (Button)findViewById(R.id.alpha_plus);
alpha_minus = (Button)findViewById(R.id.alpha_minus);
previous.setOnClickListener(listener);
next.setOnClickListener(listener);
alpha_plus.setOnClickListener(listener);
alpha_minus.setOnClickListener(listener);
}
private View.OnClickListener listener = new View.OnClickListener(){
public void onClick(View v) {
if (v == previous){
currentImgId = (currentImgId - 1 + imgId.length) % imgId.length;
imageView.setImageResource(imgId[currentImgId]);
}
if (v == next){
currentImgId = (currentImgId + 1 ) % imgId.length;
imageView.setImageResource(imgId[currentImgId]);
}
if (v == alpha_plus){
alpha += 10 ;
if (alpha > 255 ){
alpha = 255 ;
}
imageView.setAlpha(alpha);
}
if (v == alpha_minus){
alpha -= 10 ;
if (alpha < 0 ){
alpha = 0 ;
}
imageView.setAlpha(alpha);
}
}
};
}
运行结果
原创文章，作者：Maggie-Hunter，如若转载，请注明出处：https://blog.ytso.com/tech/pnotes/228182.html