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Android实现TextView文字水平滚动效果实现

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第一步:编写MarqueeText.java类,继承自TextView```java import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Canvas;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.widget.TextView;

public class MarqueeText extends TextView {
/* 是否停止滚动 /
private boolean mStopMarquee;
private String mText;
private float mCoordinateX;
private float mTextWidth;

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

public void setText(String text) {  
    this.mText = text;  
    mTextWidth = getPaint().measureText(mText);  
    if (mHandler.hasMessages(0))  
        mHandler.removeMessages(0);  
    mHandler.sendEmptyMessageDelayed(0, 2000);  
}

@SuppressLint("NewApi")  
@Override  
protected void onAttachedToWindow() {  
    mStopMarquee = false;  
    if (!(mText == null || mText.isEmpty()))  
        mHandler.sendEmptyMessageDelayed(0, 2000);  
    super.onAttachedToWindow();  
}

@Override  
protected void onDetachedFromWindow() {  
    mStopMarquee = true;  
    if (mHandler.hasMessages(0))  
        mHandler.removeMessages(0);  
    super.onDetachedFromWindow();  
}

@SuppressLint("NewApi")  
@Override  
protected void onDraw(Canvas canvas) {  
    super.onDraw(canvas);  
    if (!(mText == null || mText.isEmpty()))  
        canvas.drawText(mText, mCoordinateX, 30, getPaint());  
}

@SuppressLint("HandlerLeak")  
private Handler mHandler = new Handler() {  
    @Override  
    public void handleMessage(Message msg) {  
        switch (msg.what) {  
        case 0:  
            if (Math.abs(mCoordinateX) > (mTextWidth + 5)) {  
                mCoordinateX = 0;  
                invalidate();  
                if (!mStopMarquee) {  
                    sendEmptyMessageDelayed(0,500);  
                }  
            } else {  
                mCoordinateX -= 1;  
                invalidate();  
                if (!mStopMarquee) {  
                    sendEmptyMessageDelayed(0, 30);  
                }  
            }  
            break;  
        }  
        super.handleMessage(msg);  
    }  
};

}

第二步:编写布局文件main.xml```xml

第三步:编写SYIT_Index.java继承自Activity类```java import java.io.IOException;
import cn.superyouth.www.itools.MarqueeText;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.method.ScrollingMovementMethod;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.GridView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;

public class SYIT_Index extends Activity {
MarqueeText autoScrollTextView;

public void onCreate(Bundle savedInstanceState) {  
    super.onCreate(savedInstanceState);  
    setContentView(R.layout.main);

    autoScrollTextView = (MarqueeText) findViewById(R.id.textMsg);  
    autoScrollTextView.setTextSize(30);

    autoScrollTextView.setTextColor(Color.BLUE);  
    autoScrollTextView.setText("暂无任何预警信息!");  
    // 点击预警提示信息  
    autoScrollTextView.setOnClickListener(new OnClickListener() {  
        public void onClick(View arg0) {  
            // 进入预警信息页面  
            Intent intent = new Intent(SYIT_Index.this, SYIT_Warning.class);  
            startActivity(intent);  
        }  
    });  
 }

}
```

标签:java

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