从右到左跑马灯效果

package com.android;
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;

public class RunBackActivity extends TextView implements OnClickListener {
	public final static String TAG = RunBackActivity.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 RunBackActivity(Context context) {
		super(context);
		initView();
	}

	public RunBackActivity(Context context, AttributeSet attrs) {
		super(context, attrs);
		initView();
	}

	public RunBackActivity(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);
		}

		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];
			}

			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();
	}

	public void onDraw(Canvas canvas) {
		canvas.drawText(text, temp_view_plus_text_length - step, y, paint);
		if (!isStarting) {
			return;
		}
		step += 0.5;// 0.5为文字滚动速度。
		if (step > temp_view_plus_two_text_length)
			step = textLength;
		invalidate();

	}

	public void onClick(View v) {
		if (isStarting)
			stopScroll();
		else
			startScroll();

	}

}

 然后在Activity中调用此方法

public class MainActivity extends Activity {
	RunBackActivity autoScrollTextView;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		autoScrollTextView = (RunBackActivity)findViewById(R.id.TextViewNotice);
        autoScrollTextView.init(getWindowManager());
        autoScrollTextView.startScroll();

	}
}

 

 

在main.xml中设置

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

 <com.android.RunBackActivity
    android:id="@+id/TextViewNotice"
    android:layout_height="30px"
    android:layout_width="fill_parent"
    android:text="嘿嘿"
    android:textColor="#000"
    android:inputType="text"
    android:background="#EEE"
    android:textSize="20px">
   </com.android.RunBackActivity>

    
</LinearLayout>