跑马灯 TextView 朱雀 2023-10-05 14:14 59阅读 0赞 import android.content.Context; import android.graphics.Canvas; import android.graphics.Paint; import android.os.Parcel; import android.os.Parcelable; import android.util.AttributeSet; import android.view.Display; import android.view.View; import android.view.WindowManager; import android.view.View.OnClickListener; import android.widget.TextView; /** * 跑马灯 */ public class AutoScrollTextView extends TextView implements OnClickListener { public final static String TAG = AutoScrollTextView.class.getSimpleName(); private float textLength = 0f;//文本长度 private float viewWidth = 0f; private float step = 0f;//文字的横坐标 private float y = 0f;//文字的纵坐标 private float temp_view_plus_text_length = 0.0f;//用于计算的临时变量 private float temp_view_plus_two_text_length = 0.0f;//用于计算的临时变量 public boolean isStarting = false;//是否开始滚动 private Paint paint = null;//绘图样式 private String text = "";//文本内容 public AutoScrollTextView(Context context) { super(context); initView(); } public AutoScrollTextView(Context context, AttributeSet attrs) { super(context, attrs); initView(); } public AutoScrollTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initView(); } private void initView() { setOnClickListener(this); } public void init(WindowManager windowManager) { paint = getPaint(); text = getText().toString(); textLength = paint.measureText(text); viewWidth = getWidth(); if (viewWidth == 0) { if (windowManager != null) { Display display = windowManager.getDefaultDisplay(); viewWidth = display.getWidth(); } } step = textLength; temp_view_plus_text_length = viewWidth + textLength; temp_view_plus_two_text_length = viewWidth + textLength * 2; y = getTextSize() + getPaddingTop(); } @Override public Parcelable onSaveInstanceState() { Parcelable superState = super.onSaveInstanceState(); SavedState ss = new SavedState(superState); ss.step = step; ss.isStarting = isStarting; return ss; } @Override public void onRestoreInstanceState(Parcelable state) { if (!(state instanceof SavedState)) { super.onRestoreInstanceState(state); return; } SavedState ss = (SavedState) state; super.onRestoreInstanceState(ss.getSuperState()); step = ss.step; isStarting = ss.isStarting; } public static class SavedState extends BaseSavedState { public boolean isStarting = false; public float step = 0.0f; SavedState(Parcelable superState) { super(superState); } @Override public void writeToParcel(Parcel out, int flags) { super.writeToParcel(out, flags); out.writeBooleanArray(new boolean[]{isStarting}); out.writeFloat(step); } public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { public SavedState[] newArray(int size) { return new SavedState[size]; } @Override public SavedState createFromParcel(Parcel in) { return new SavedState(in); } }; private SavedState(Parcel in) { super(in); boolean[] b = null; in.readBooleanArray(b); if (b != null && b.length > 0) isStarting = b[0]; step = in.readFloat(); } } public void startScroll() { isStarting = true; invalidate(); } public void stopScroll() { isStarting = false; invalidate(); } @Override public void onDraw(Canvas canvas) { canvas.drawText(text, temp_view_plus_text_length - step, y, paint); if (!isStarting) { return; } step += 5;//0.5为文字滚动速度。 if (step > temp_view_plus_two_text_length) step = textLength; invalidate(); } @Override public void onClick(View v) { if (isStarting) stopScroll(); else startScroll(); } }
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