Android文字自滾動textview

標籤：

自訂AutoScrollTextView繼承至TextView，在onDraw()中設定文字的X軸位移量加1並重新整理，以實現文字從右向左移動的效果。

public class AutoScrollTextView extends TextView implements OnClickListener {private String Tag = "AutoScrollTextView";/** 文本長度 */private float textLength = 0f;/** 螢幕或空間的寬度 */private float viewWidth = 0f;/** 文字的橫座標 */private float step = 0f;/** 文字的縱座標 */private float y = 0f;/** 用於計算的臨時變數 */private float temp_view_plus_text_length = 0.0f;/** 用於計算的臨時變數 */private float temp_view_plus_two_text_length = 0.0f;/** 是否開始滾動 */public boolean isStarting = false;/** 繪圖樣式 */private Paint paint = null;/** 常值內容 */private String text = "";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() {paint = getPaint();setOnClickListener(this);}public void init(WindowManager windowManager) {L.i(Tag, "init paint ===="+paint);text = getText().toString();paint.setColor(Color.rgb(251, 163, 68));textLength = paint.measureText(text);L.e("lg", "text ==="+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();}@Overridepublic Parcelable onSaveInstanceState() {Parcelable superState = super.onSaveInstanceState();SavedState ss = new SavedState(superState);ss.step = step;ss.isStarting = isStarting;return ss;}@Overridepublic 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);}@Overridepublic 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];}@Overridepublic SavedState createFromParcel(Parcel in) {return new SavedState(in);}};@SuppressWarnings("unused")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();}@Overridepublic void onDraw(Canvas canvas) {canvas.drawText(text, temp_view_plus_text_length - step, y, paint);if (!isStarting) {return;}step += 1;// 0.5為文字捲動速度。if (step > temp_view_plus_two_text_length)step = textLength;invalidate();}@Overridepublic void onClick(View arg0) {// TODO Auto-generated method stubif (isStarting)stopScroll();elsestartScroll();}}

在xml中使用：

<com.demo.view.AutoScrollTextView        android:id="@+id/auto_textview"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="center_horizontal"        android:padding="5dp" />

在Java中使用：

private AutoScrollTextView auto_tv;auto_tv = (AutoScrollTextView) findViewById(R.id.auto_textview);auto_tv.setText(msg);auto_tv.init(getWindowManager());auto_tv.startScroll();

Android文字自滾動textview