最近在看Google的一个开源项目 Topeka ,想研究一下,了解大神都怎么写代码的.
官方介绍只有一句话：一部有趣的问答应用！
传送门
在app的登录页面有一个头像选择,实现了圆形头像,选择头像时ImageView外圈增加一个圆圈,而且适配了5.0以上的版本.实现也很优雅.于是我就仿照写了一个圆角的 ImageView.
效果如下：屏幕中间的就是自定义的 圆角ImageView
布局文件如下:
使用方法也很简单,在布局文件中使用就可以了:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<com.sync.customviewstudy.view.RoundImageView
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_centerInParent="true"
android:id="@+id/img"
android:src="@mipmap/avatar_12_raster"
/>
</RelativeLayout>先上自定义ImageVIew的代码:
AvatarView.java
/**
* Description: 圆形头像
* Author：Mari on 2017-07-25 22:30
* Contact：289168296@qq.com
*/
public class RoundImageView extends ImageView {
public RoundImageView(Context context) {
super(context);
}
public RoundImageView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
}
public RoundImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override public void setImageDrawable(@Nullable Drawable drawable) {
if (ApiLevelHelper.isAtLeast(Build.VERSION_CODES.LOLLIPOP)) {
setClipToOutline(true);
super.setImageDrawable(drawable);
} else {
BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
RoundedBitmapDrawable roundedDrawable =
RoundedBitmapDrawableFactory.create(getResources(), bitmapDrawable.getBitmap());
roundedDrawable.setCircular(true);
super.setImageDrawable(roundedDrawable);
}
}
// onLayout() 之后调用
@Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
if (ApiLevelHelper.isLowerThan(Build.VERSION_CODES.LOLLIPOP)) {
return;
}
if (w > 0 && h > 0) {
setOutlineProvider(new RoundOutlineProvider(Math.min(w, h)));
}
}
}代码很少,在 setImageDrawable,onSizeChanged 两个方法中区分 Android 5.0 即以上版本和5.0一下2个版本不同的处理方式, 5.0 以下版本使用 RoundedBitmapDrawable 实现圆形 drawable 资源,
而在 5.0 以上版本使用 RoundOutlineProvider 实现圆角 drawable 资源. ‘RoundOutlineProvider’ 继承 ViewOutlineProvider 这个类是在 android.view.ViewOutlineProvider 包下面,大家想要了解更多可以自己去找下资料看看哈.
RoundOutlineProvider.java
/**
* Description: Creates round outlines for views.
* Author：Mari on 2017-07-25 22:30
* Contact：289168296@qq.com
*/
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP) public class RoundOutlineProvider extends ViewOutlineProvider {
private final int mSize;
public RoundOutlineProvider(int size) {
mSize = size;
}
@Override public void getOutline(View view, Outline outline) {
outline.setOval(0, 0, mSize, mSize);
}
}ApiLevelHelper.java
/**
* Encapsulates checking api levels.
*/
public class ApiLevelHelper {
private ApiLevelHelper() {
//no instance
}
/**
* Checks if the current api level is at least the provided value.
*
* @param apiLevel One of the values within {@link Build.VERSION_CODES}.
* @return <code>true</code> if the calling version is at least <code>apiLevel</code>.
* Else <code>false</code> is returned.
*/
public static boolean isAtLeast(int apiLevel) {
return Build.VERSION.SDK_INT >= apiLevel;
}
/**
* Checks if the current api level is at lower than the provided value.
*
* @param apiLevel One of the values within {@link Build.VERSION_CODES}.
* @return <code>true</code> if the calling version is lower than <code>apiLevel</code>.
* Else <code>false</code> is returned.
*/
public static boolean isLowerThan(int apiLevel) {
return Build.VERSION.SDK_INT < apiLevel;
}
}