Android跑馬燈效果

標籤：layout   textview   canvas   

布局檔案:

<LinearLayout        android:layout_width="fill_parent"        android:layout_height="60dip" >        <com.example.guanggao.AutoScrollTextView            android:id="@+id/tv_notice"            android:layout_width="fill_parent"            android:layout_height="fill_parent"            android:textSize="25sp" />    </LinearLayout>

代碼:

AutoScrollTextView:

public class AutoScrollTextView extends TextView {public final static String TAG = AutoScrollTextView.class.getSimpleName();private float textLength = 0f;// 文本長度private float viewWidth = 0f;private float step = 0f;// 文字的橫座標private float y = 0f;// 文字的縱座標private float temp_view_plus_text_length = 0.0f;// 用於計算的臨時變??private float temp_view_plus_two_text_length = 0.0f;// 用於計算的臨時變??public boolean isStarting = false;// 是否??始滾??private Paint paint = null;// 繪圖樣式private String text = "";// 常值內容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();}@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);}};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) {if (!isStarting) {return;}canvas.drawText(text, temp_view_plus_text_length - step, y, paint);step += 2;// 文字捲動速度??if (step > temp_view_plus_two_text_length)step = textLength;invalidate();}// @Override// public void onClick(View v) {// if (isStarting)// stopScroll();// else// startScroll();//// }}

MainActivity:

private void getNotice() {// TODO Auto-generated method stubtv_notice.setText(文字);tv_notice.init(getWindowManager());tv_notice.startScroll();}

Android跑馬燈效果