Android 如何实现竖排文字显示？



在android.graphics.Canvas类中有个沿路径画字的方法

void drawTextOnPath(String text, Path path, float hOffset, float vOffset, Paint paint)

Draw the text, with origin at (x,y), using the specified paint, along the specified path.

void drawTextOnPath(char[] text, int index, int count, Path path, float hOffset, float vOffset, Paint paint)

Draw the text, with origin at (x,y), using the specified paint, along the specified path.

Test.java代码://需要在layout中定义Test，且设置背景,在java代码中设置test Text

public class Test extends View {

private Paint paint;

private Path path;

private Matrix matrix;

private int width = -1;

private int height = -1;

private float left = 3;

private float top = 18;

private String title = "";

BitmapDrawable drawable = (BitmapDrawable) getBackground();

public Test(Context context, AttributeSet attrs) {

super(context, attrs);

paint = new Paint();

paint.setColor(Color.WHITE);//定义字体颜色

paint.setTextSize(14);//定义字体大小

path = new Path();

path.lineTo(0,500);//定义字符路径

matrix = new Matrix();

Log.v("onMeasure", "2");

}

@Override

protected void onDraw(Canvas canvas) {

//画背景

Bitmap b = Bitmap.createBitmap(drawable.getBitmap(),0,0,width,height);

canvas.drawBitmap(b, matrix, paint);

//画字

showText(canvas, title);

}

private void showText(Canvas canvas, String text){

float w;

final int len = text.length();

float py = 0 + top;

for(int i=0; i<len; i ++){

char c = text.charAt(i);

w = paint.measureText(text, i, i+1);//获取字符宽度

StringBuffer b = new StringBuffer();

b.append(c);

if(py > 81){//定义字的范围

return;

}

if(isChinese(c)){

py += w;

if(py > 81){

return;

}

canvas.drawText(b.toString(), left, py, paint); //中文处理方法

}else {

canvas.drawTextOnPath(b.toString(), path, py, -left-2, paint);//其他文字处理方法

py += w;

}

}

}

public void setText(String title){

this.title = title;

}

public String getText(){

return title;

}

private boolean isChinese(char c) {

Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);

if (ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS

|| ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS

|| ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A

|| ub == Character.UnicodeBlock.GENERAL_PUNCTUATION

|| ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION

|| ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS) {

return true;

}

return false;

}

//重写View大小方法，使view大小为背景图片大小

@Override

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

// super.onMeasure(widthMeasureSpec, heightMeasureSpec);

if (null != getBackground()) {

int h = drawable.getIntrinsicHeight();

int w = drawable.getIntrinsicWidth();

Log.v("onMeasure", "null != getBackground() h:" + h + " w:" + w);

width = w;

height = h;

setMeasuredDimension(w, h);

} else {

width = widthMeasureSpec;

height = heightMeasureSpec;

super.measure(widthMeasureSpec, heightMeasureSpec);

}

}

}

在Android中，若要通过程序改变屏幕显示的方向，必须要覆盖setRequestedOrientation()方法，而若要取得目前的屏幕方向，则需要访问getRequestedOrientation()方法。本范例为求简要示范更改做法，设计了一个按钮，当单击按钮的同时，判断当下的屏幕方向，例如竖排（PORTRAIT），则将其更改为横排（LANDSCAPE）；若为横排（LANDSCAPE），则将其更改为竖排（PORTRAIT）