一个很快的问题,但我似乎找不到任何例子...... 我想通过Canvas
将多行文本写入自定义的View
中,在onDraw()
中我有:
...
String text = "This is\nmulti-line\ntext";
canvas.drawText(text, 100, 100, mTextPaint);
...
我本希望这样做可以实现换行,但是我看到的是一些加密的字符,它们应该在\n
的位置上。
欢迎提供任何指针。
保罗
一个很快的问题,但我似乎找不到任何例子...... 我想通过Canvas
将多行文本写入自定义的View
中,在onDraw()
中我有:
...
String text = "This is\nmulti-line\ntext";
canvas.drawText(text, 100, 100, mTextPaint);
...
我本希望这样做可以实现换行,但是我看到的是一些加密的字符,它们应该在\n
的位置上。
欢迎提供任何指针。
保罗
我找到了另一种使用静态布局的方法。这里的代码供任何人参考:
TextPaint mTextPaint=new TextPaint();
StaticLayout mTextLayout = new StaticLayout(mText, mTextPaint, canvas.getWidth(), Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
canvas.save();
// calculate x and y position where your text will be placed
textX = ...
textY = ...
canvas.translate(textX, textY);
mTextLayout.draw(canvas);
canvas.restore();
canvas.getWidth()
应该改为 getWidth() - getPaddingLeft() - getPaddingRight()
,以考虑视图的填充。此外,请注意只有在文本或视图大小更改时才能计算 StaticLayout,并且可以在不构建新布局的情况下进行绘制,这可能更好! - Jules只需遍历每一行:
int x = 100, y = 100;
for (String line: text.split("\n")) {
canvas.drawText(line, x, y, mTextPaint);
y += mTextPaint.descent() - mTextPaint.ascent();
}
很遗憾,Android不知道\n
是什么意思。你需要剔除\n
,然后偏移Y值以使文本在下一行显示。像这样:
canvas.drawText("This is", 100, 100, mTextPaint);
canvas.drawText("multi-line", 100, 150, mTextPaint);
canvas.drawText("text", 100, 200, mTextPaint);
drawText()
函数,对吗? - Unpossible我已经写了一个完整的示例
colors.xml
<color name="transparentBlack">#64000000</color>
Java类
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.amit);
ImageView imageView = (ImageView)findViewById(R.id.imageView);
imageView.setImageBitmap(drawTextToBitmap(this, bm, "Name: Kolala\nDate: Dec 23 2016 12:47 PM, \nLocation: 440 Banquets & Restaurents"));
}
public Bitmap drawTextToBitmap(Context gContext,
Bitmap bitmap,
String gText) {
Resources resources = gContext.getResources();
float scale = resources.getDisplayMetrics().density;
android.graphics.Bitmap.Config bitmapConfig =
bitmap.getConfig();
// set default bitmap config if none
if(bitmapConfig == null) {
bitmapConfig = android.graphics.Bitmap.Config.ARGB_8888;
}
// resource bitmaps are imutable,
// so we need to convert it to mutable one
bitmap = bitmap.copy(bitmapConfig, true);
Canvas canvas = new Canvas(bitmap);
// new antialised Paint
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
// text color - #3D3D3D
paint.setColor(Color.WHITE);
// text size in pixels
paint.setTextSize((int) (25 * scale));
// text shadow
paint.setShadowLayer(1f, 0f, 1f, Color.WHITE);
// draw text to the Canvas center
Rect bounds = new Rect();
int noOfLines = 0;
for (String line: gText.split("\n")) {
noOfLines++;
}
paint.getTextBounds(gText, 0, gText.length(), bounds);
int x = 20;
int y = (bitmap.getHeight() - bounds.height()*noOfLines);
Paint mPaint = new Paint();
mPaint.setColor(getResources().getColor(R.color.transparentBlack));
int left = 0;
int top = (bitmap.getHeight() - bounds.height()*(noOfLines+1));
int right = bitmap.getWidth();
int bottom = bitmap.getHeight();
canvas.drawRect(left, top, right, bottom, mPaint);
for (String line: gText.split("\n")) {
canvas.drawText(line, x, y, paint);
y += paint.descent() - paint.ascent();
}
return bitmap;
}
}
int noOfLines = gText.split("\n").length
。(注:原文中的 gText 表示一个字符串变量,split() 方法可以根据给定的分隔符将字符串拆分为数组。此处代码的意思是将 gText 字符串按照换行符 "\n" 进行拆分,然后返回数组的长度作为行数。) - Tomaszimport android.graphics.Canvas;
import android.graphics.Paint;
public class mdCanvas
{
private Canvas m_canvas;
public mdCanvas(Canvas canvas)
{
m_canvas = canvas;
}
public void drawMultiline(String str, int x, int y, Paint paint)
{
for (String line: str.split("\n"))
{
m_canvas.drawText(line, x, y, paint);
y += -paint.ascent() + paint.descent();
}
}
}
void drawMultiLineText(String str, float x, float y, Paint paint, Canvas canvas) {
String[] lines = str.split("\n");
float txtSize = -paint.ascent() + paint.descent();
if (paint.getStyle() == Style.FILL_AND_STROKE || paint.getStyle() == Style.STROKE){
txtSize += paint.getStrokeWidth(); //add stroke width to the text size
}
float lineSpace = txtSize * 0.2f; //default line spacing
for (int i = 0; i < lines.length; ++i) {
canvas.drawText(lines[i], x, y + (txtSize + lineSpace) * i, paint);
}
}
它会正常工作。我已经测试过了。
public Bitmap drawMultilineTextToBitmap(Context gContext,
int gResId,
String gText) {
// prepare canvas
Resources resources = gContext.getResources();
float scale = resources.getDisplayMetrics().density;
Bitmap bitmap = BitmapFactory.decodeResource(resources, gResId);
android.graphics.Bitmap.Config bitmapConfig = bitmap.getConfig();
// set default bitmap config if none
if(bitmapConfig == null) {
bitmapConfig = android.graphics.Bitmap.Config.ARGB_8888;
}
// resource bitmaps are imutable,
// so we need to convert it to mutable one
bitmap = bitmap.copy(bitmapConfig, true);
Canvas canvas = new Canvas(bitmap);
// new antialiased Paint
TextPaint paint=new TextPaint(Paint.ANTI_ALIAS_FLAG);
// text color - #3D3D3D
paint.setColor(Color.rgb(61, 61, 61));
// text size in pixels
paint.setTextSize((int) (14 * scale));
// text shadow
paint.setShadowLayer(1f, 0f, 1f, Color.WHITE);
// set text width to canvas width minus 16dp padding
int textWidth = canvas.getWidth() - (int) (16 * scale);
// init StaticLayout for text
StaticLayout textLayout = new StaticLayout(
gText, paint, textWidth, Layout.Alignment.ALIGN_CENTER, 1.0f, 0.0f, false);
// get height of multiline text
int textHeight = textLayout.getHeight();
// get position of text's top left corner
float x = (bitmap.getWidth() - textWidth)/2;
float y = (bitmap.getHeight() - textHeight)/2;
// draw text to the Canvas center
canvas.save();
canvas.translate(x, y);
textLayout.draw(canvas);
canvas.restore();
return bitmap;
}
来源: http://www.skoumal.net/en/android-drawing-multiline-text-on-bitmap/
本文介绍了如何在Android中将多行文本绘制到位图上。您需要使用Paint类和Canvas对象来设置字体、颜色和对齐方式,然后使用StaticLayout类将文本布局到位图上。请注意,这种方法适用于较短的文本段落,否则可能会出现性能问题。canvas.getFontSpacing()
作为增量即可。出于好奇,我自己尝试过,它适用于任何字号。试一试
Paint paint1 = new Paint();
paint1.setStyle(Paint.Style.FILL);
paint1.setAntiAlias(true);
paint1.setColor(Color.BLACK);
paint1.setTextSize(15);
TextView tv = new TextView(context);
tv.setTextColor(Color.BLACK);
LinearLayout.LayoutParams llp = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
llp.setMargins(5, 2, 0, 0); // llp.setMargins(left, top, right, bottom);
tv.setLayoutParams(llp);
tv.setTextSize(10);
String text="this is good to see you , i am the king of the team";
tv.setText(text);
tv.setDrawingCacheEnabled(true);
tv.measure(MeasureSpec.makeMeasureSpec(canvas.getWidth(), MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(canvas.getHeight(), MeasureSpec.EXACTLY));
tv.layout(0, 0, tv.getMeasuredWidth(), tv.getMeasuredHeight());
canvas.drawBitmap(tv.getDrawingCache(), 5, 10, paint1);
tv.setDrawingCacheEnabled(false);
我重新使用了GreenBee提出的解决方案,并编写了一个函数,在指定的边界内绘制一些多行文本,如果出现截断,则在结尾处添加“...”:
public static void drawMultiLineEllipsizedText(final Canvas _canvas, final TextPaint _textPaint, final float _left,
final float _top, final float _right, final float _bottom, final String _text) {
final float height = _bottom - _top;
final StaticLayout measuringTextLayout = new StaticLayout(_text, _textPaint, (int) Math.abs(_right - _left),
Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
int line = 0;
final int totalLineCount = measuringTextLayout.getLineCount();
for (line = 0; line < totalLineCount; line++) {
final int lineBottom = measuringTextLayout.getLineBottom(line);
if (lineBottom > height) {
break;
}
}
line--;
if (line < 0) {
return;
}
int lineEnd;
try {
lineEnd = measuringTextLayout.getLineEnd(line);
} catch (Throwable t) {
lineEnd = _text.length();
}
String truncatedText = _text.substring(0, Math.max(0, lineEnd));
if (truncatedText.length() < 3) {
return;
}
if (truncatedText.length() < _text.length()) {
truncatedText = truncatedText.substring(0, Math.max(0, truncatedText.length() - 3));
truncatedText += "...";
}
final StaticLayout drawingTextLayout = new StaticLayout(truncatedText, _textPaint, (int) Math.abs(_right
- _left), Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
_canvas.save();
_canvas.translate(_left, _top);
drawingTextLayout.draw(_canvas);
_canvas.restore();
}
Layout
而不是直接调用Canvas.drawText
。这个问答展示了如何使用StaticLayout
来绘制多行文本。 - Suragch