TextView跑馬燈狀態監聽
阿新 • • 發佈：2019-01-11
最近UI有需求是 文字過長用跑馬燈顯示，跑完一遍後超出文字狀態用 Marquee.END的模式，Android本身沒有提供跑馬燈狀態監聽的介面，本打算自定義一個TextView，定時去計算，雖然可以實現，但是效果應該沒原生的好，於是決定使用反射的方式去實現，具體程式碼如下
package com.dbn.dialogtest; import android.content.Context; import android.support.annotation.Nullable; import android.support.v7.widget.AppCompatTextView; import android.util.AttributeSet; import android.util.Log; import android.view.Choreographer; import android.widget.TextView; import java.lang.reflect.Field; import java.lang.reflect.Method; /** * Created by Administrator on 2018/5/8. */ public class MyTextView extends TextView { private String TAG = MyTextView.class.getSimpleName(); private static final byte MARQUEE_STOPPED = 0x0; private static final byte MARQUEE_STARTING = 0x1; private static final byte MARQUEE_RUNNING = 0x2; private OnMarqueeListener onMarqueeListener; public MyTextView(Context context) { super(context); } public MyTextView(Context context, @Nullable AttributeSet attrs) { super(context, attrs); } public MyTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } private void init(Context context) { } @Override public void setSelected(boolean selected) { super.setSelected(selected); } @Override public boolean post(Runnable action) { return super.post(action); } public void setMarqueeListener(OnMarqueeListener onMarqueeListener) { this.onMarqueeListener = onMarqueeListener; try { Field marquee = this.getClass().getSuperclass().getDeclaredField("mMarquee"); if(marquee != null) { marquee.setAccessible(true); Object obj = marquee.get(this); if(obj != null) { Class cls = obj.getClass(); Field field = cls.getDeclaredField("mStatus"); if(field != null) { field.setAccessible(true); } Field field1 = cls.getDeclaredField("mRestartCallback"); if(field1 != null) { field1.setAccessible(true); field1.set(obj, mRestartCallback); } } } }catch (Exception e) { e.printStackTrace(); } } private Choreographer.FrameCallback mRestartCallback = new Choreographer.FrameCallback() { @Override public void doFrame(long frameTimeNanos) { try { Field marquee = MyTextView.this.getClass().getSuperclass().getDeclaredField("mMarquee"); if(marquee != null) { marquee.setAccessible(true); Object obj = marquee.get(MyTextView.this); if(obj != null) { Class cls = obj.getClass(); Field field = cls.getDeclaredField("mStatus"); if(field != null) { field.setAccessible(true); byte mStatus = ((Byte)field.get(obj)).byteValue(); if(mStatus == MARQUEE_RUNNING) { Field field1 = cls.getDeclaredField("mRepeatLimit"); field1.setAccessible(true); int mRepeatLimit = ((Integer)field1.get(obj)).intValue();; if(mRepeatLimit >= 0) { mRepeatLimit--; } if(onMarqueeListener != null) { onMarqueeListener.onMarqueeRepeateChanged(mRepeatLimit); } Method method = cls.getDeclaredMethod("start", Integer.TYPE); method.setAccessible(true); method.invoke(obj, mRepeatLimit); } } } } }catch (Exception e) { e.printStackTrace(); } } };
//狀態監聽介面
public interface OnMarqueeListener {
void onMarqueeRepeateChanged(int repeatLimit);
}
}