自定义视图在 Android Lollipop 中不起作用

Question

我正在创建自定义视图。我在布局 XML 中为视图添加了下面一行 xmlns:my="http://schemas.android.com/apk/res-auto

<RelattiveLayout  xmlns:my="http://schemas.android.com/apk/res-auto">
<com.clippingtest.ViewClip
    android:layout_below="@id/tv"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content">

</com.clippingtest.ViewClip>
</RelativeLayout>

在 MainActivity 中添加了该视图。除了 Lollipop，我在所有版本中都可以正常工作。它在这一行中显示 InflateException (' setContentView(R.layout.activity_main);' )，应用程序立即在棒棒糖中崩溃。我如何为棒棒糖创建自定义视图。

自定义视图代码：

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    int width = getWidth();

    Paint paint = new Paint();
    paint.setStyle(Paint.Style.FILL);
    paint.setColor(Color.BLUE);
    paint.setStrokeWidth(2);
    Path path = new Path();
    path.moveTo(0,0);
    path.lineTo(width-180, 80);
    path.lineTo(width, 60);
    path.close();
    canvas.drawPath(path, paint);

}

错误代码：

   06-27 17:31:44.365  28812-28812/com.clippingtest E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.clippingtest, PID: 28812
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.clippingtest/com.clippingtest.MainActivity}: android.view.InflateException: Binary XML file line #13: Error inflating class com.clippingtest.ViewClip
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
        at android.app.ActivityThread.access0(ActivityThread.java:151)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5257)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
 Caused by: android.view.InflateException: Binary XML file line #13: Error inflating class com.clippingtest.ViewClip
        at android.view.LayoutInflater.createView(LayoutInflater.java:616)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:743)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
        at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:249)
        at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:106)
        at com.clippingtest.MainActivity.onCreate(MainActivity.java:14)
        at android.app.Activity.performCreate(Activity.java:5990)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)

在

android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390) at android.app.ActivityThread.access0(ActivityThread.java:151)

 Caused by: java.lang.NoSuchMethodException: <init> [class android.content.Context, interface android.util.AttributeSet]
        at java.lang.Class.getConstructor(Class.java:531)
        at java.lang.Class.getConstructor(Class.java:495)
        at

Answer 1

添加此构造函数后尝试

public ViewClip(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);

    }

Answer 2

您需要添加如下所示的构造函数：

public ViewClip(Context context, AttributeSet attrs)

从堆栈跟踪中可以清楚地看出这一点： Caused by: java.lang.NoSuchMethodException: <init> [class android.content.Context, interface android.util.AttributeSet]

表示缺少带有 Context 和 AttributeSet 参数类型的 <init>（构造函数）。

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