Android----[转载]TextView跑马灯的两种实现 - zhengbeibei

Android----[转载]TextView跑马灯的两种实现

[转载]TextView跑马灯的两种实现

(2012-07-02 14:21:57)

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原文地址：TextView跑马灯的两种实现作者：dylan_huang

普通的TextView可以实现跑马灯，但是只有当焦点在它上面时才有效。如何做一个自动的跑马灯呢？第一种：继承TextView，然后重写isFocused()方法就可以了，简单！

Java代码

import android.content.Context;
import android.util.AttributeSet;
import android.widget.TextView;
public class ScrollForeverTextView extends TextView {
public ScrollForeverTextView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
public ScrollForeverTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ScrollForeverTextView(Context context, AttributeSet attrs,
int defStyle) {
super(context, attrs, defStyle);
}
@Override
public boolean isFocused() {
return true;
}
}

使用时同TextView一样：

Xml代码

<com.ql.view.ScrollForeverTextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textSize="30px"
android:singleLine="true"
android:ellipsize="marquee"
android:marqueeRepeatLimit="marquee_forever"
android:textColor="@color/red"
android:text="1234567890wwwwwwwwwwwwwwwwwwwwww1234567890"
android:focusable="true"
/>

第2种：还是继承TextView，重写onDraw()，在onDraw中不停的重绘。

Java代码

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 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 CharSequence text = "";// 文本内容
private float speed = 0.5f;
private int textColor=0xFF000000;
public int getTextColor() {
return textColor;
}
public void setTextColor(int color) {
this.textColor = color;
}
public float getSpeed() {
return speed;
}
public void setSpeed(float speed) {
this.speed = speed;
}
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(float width) {
text=super.getText();
paint = super.getPaint();
// Paint paint=new Paint();
text = getText().toString();
textLength = paint.measureText(text.toString());
// viewWidth = getWidth();
// if (viewWidth == 0) {
// if (windowManager != null) {
// Display display = windowManager.getDefaultDisplay();
// viewWidth = display.getWidth();
// }
// }
viewWidth=width;
step = textLength;
temp_view_plus_text_length = viewWidth + textLength;
temp_view_plus_two_text_length = viewWidth + textLength * 2;
y = getTextSize() + getPaddingTop();
paint.setColor(textColor);
}
@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) {
// super.onDraw(canvas);
canvas.drawText(text,0,text.length(), temp_view_plus_text_length - step, y, paint);
if (!isStarting) {
return;
}
step += speed;
if (step > temp_view_plus_two_text_length)
step = textLength;
invalidate();
}
@Override
public void onClick(View v) {
if (isStarting)
stopScroll();
else
startScroll();
}
}

使用：

Java代码

marquee = (AutoScrollTextView) findViewById(R.id.marquee);
// marquee.setText(String.format(getResources().getString(R.string.marquee0),Consts.termno,"2010-12-28"));
marquee.setText("上证指数3000.15 6.81(0.37%)深圳成指3000.15 6.81(0.37%)");
// marquee.setTextColor(0xffff0000);//注意：颜色必须在这里设置，xml中设置无效！默认黑色。
//如果想改变跑马灯的文字内容或者文字效果，则在调用完setText方法之后，需要再调用一下init(width)方法，重新进行初始化和相关参数的计算。
marquee.setSpeed(1.5f);
marquee.init(width);//width通常就是屏幕宽！
marquee.startScroll();

这2种跑马灯稍微有点区别，需要掂量着使用。第1种跑马灯不能设置速度，并且要超过一行才会滚动。第2种跑马灯只能设置单一颜色，且需要在代码中设置，不能同时设置多种颜色。速度设的不要过大(<= 2.0f)，否则停顿现象比较明显。

posted on 2012-12-25 11:44 zhengbeibei 阅读(427) 评论(0) 编辑收藏举报

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