我创建了TextView的子类，它与标准TextViews一起使用。问题是默认情况下应用于标准TextView的样式不会应用于我的自定义TextView。我的自定义TextView是否有办法继承父级的风格？
自定义视图：
import android.content.Context;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.widget.TextView;
/**
* Text view that auto adjusts text size to fit within the view.
* If the text size equals the minimum text size and still does not
* fit, append with an ellipsis.
*/
public class AutoResizeTextView extends TextView {
// Minimum text size for this text view
public static final float MIN_TEXT_SIZE = 20;
// Interface for resize notifications
public interface OnTextResizeListener {
void onTextResize(TextView textView, float oldSize, float newSize);
}
// Our ellipse string
private static final String mEllipsis = "...";
// Registered resize listener
private OnTextResizeListener mTextResizeListener;
// Flag for text and/or size changes to force a resize
private boolean mNeedsResize = false;
// Text size that is set from code. This acts as a starting point for resizing
private float mTextSize;
// Temporary upper bounds on the starting text size
private float mMaxTextSize = 0;
// Lower bounds for text size
private float mMinTextSize = MIN_TEXT_SIZE;
// Text view line spacing multiplier
private float mSpacingMult = 1.0f;
// Text view additional line spacing
private float mSpacingAdd = 0.0f;
// Add ellipsis to text that overflows at the smallest text size
private boolean mAddEllipsis = true;
private float mDefaultTextSize;
// Default constructor override
public AutoResizeTextView(Context context) {
this(context, null);
}
// Default constructor when inflating from XML file
public AutoResizeTextView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
// Default constructor override
public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs);
mTextSize = getTextSize();
mDefaultTextSize = mTextSize;
}
/**
* When text changes, set the force resize flag to true and reset the text size.
*/
@Override
protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) {
mNeedsResize = true;
// Since this view may be reused, it is good to reset the text size
resetTextSize();
}
/**
* If the text view size changed, set the force resize flag to true
*/
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
if (w != oldw || h != oldh) {
mNeedsResize = true;
}
}
/**
* Register listener to receive resize notifications
* @param listener
*/
public void setOnResizeListener(OnTextResizeListener listener) {
mTextResizeListener = listener;
}
/**
* Override the set text size to update our internal reference values
*/
@Override
public void setTextSize(float size) {
super.setTextSize(size);
mTextSize = getTextSize();
}
/**
* Override the set text size to update our internal reference values
*/
@Override
public void setTextSize(int unit, float size) {
super.setTextSize(unit, size);
mTextSize = getTextSize();
}
/**
* Override the set line spacing to update our internal reference values
*/
@Override
public void setLineSpacing(float add, float mult) {
super.setLineSpacing(add, mult);
mSpacingMult = mult;
mSpacingAdd = add;
}
/**
* Set the upper text size limit and invalidate the view
* @param maxTextSize
*/
public void setMaxTextSize(float maxTextSize) {
mMaxTextSize = maxTextSize;
requestLayout();
invalidate();
}
/**
* Return upper text size limit
* @return
*/
public float getMaxTextSize() {
return mMaxTextSize;
}
/**
* Set the lower text size limit and invalidate the view
* @param minTextSize
*/
public void setMinTextSize(float minTextSize) {
mMinTextSize = minTextSize;
requestLayout();
invalidate();
}
/**
* Return lower text size limit
* @return
*/
public float getMinTextSize() {
return mMinTextSize;
}
/**
* Set flag to add ellipsis to text that overflows at the smallest text size
* @param addEllipsis
*/
public void setAddEllipsis(boolean addEllipsis) {
mAddEllipsis = addEllipsis;
}
/**
* Return flag to add ellipsis to text that overflows at the smallest text size
* @return
*/
public boolean getAddEllipsis() {
return mAddEllipsis;
}
/**
* Reset the text to the original size
*/
public void resetTextSize() {
if (mTextSize > 0) {
mTextSize = mDefaultTextSize;
super.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize);
}
}
/**
* Resize text after measuring
*/
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
if (changed || mNeedsResize) {
int widthLimit = (right - left) - getCompoundPaddingLeft() - getCompoundPaddingRight();
int heightLimit = (bottom - top) - getCompoundPaddingBottom() - getCompoundPaddingTop();
resizeText(widthLimit, heightLimit);
}
super.onLayout(changed, left, top, right, bottom);
}
/**
* Resize the text size with default width and height
*/
public void resizeText() {
int heightLimit = getHeight() - getPaddingBottom() - getPaddingTop();
int widthLimit = getWidth() - getPaddingLeft() - getPaddingRight();
resizeText(widthLimit, heightLimit);
}
/**
* Resize the text size with specified width and height
* @param widthLimit
* @param heightLimit
*/
public void resizeText(int widthLimit, int heightLimit) {
CharSequence text = getText();
// Do not resize if the view does not have dimensions or there is no text
if (text == null || text.length() == 0 || heightLimit <= 0 || widthLimit <= 0 || mTextSize == 0) {
return;
}
if (getTransformationMethod() != null) {
text = getTransformationMethod().getTransformation(text, this);
}
// Get the text view's paint object
TextPaint textPaint = getPaint();
// Store the current text size
float currentTextSize = textPaint.getTextSize();
// If there is a max text size set, use the lesser of that and the default text size
float targetTextSize = mMaxTextSize > 0 ? Math.min(mTextSize, mMaxTextSize) : mTextSize;
// Get the required text height
int textHeight = getTextHeight(text, textPaint, widthLimit, targetTextSize);
// Until we either fit within our text view or we had reached our min text size, incrementally try smaller sizes
while (textHeight > heightLimit && targetTextSize > mMinTextSize) {
targetTextSize = Math.max(targetTextSize - 2, mMinTextSize);
textHeight = getTextHeight(text, textPaint, widthLimit, targetTextSize);
}
// If we had reached our minimum text size and still don't fit, append an ellipsis
if (mAddEllipsis && targetTextSize == mMinTextSize && textHeight > heightLimit) {
// Draw using a static layout
// modified: use a copy of TextPaint for measuring
TextPaint paint = new TextPaint(textPaint);
// Draw using a static layout
StaticLayout layout = new StaticLayout(text, paint, widthLimit, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, false);
// Check that we have a least one line of rendered text
if (layout.getLineCount() > 0) {
// Since the line at the specific vertical position would be cut off,
// we must trim up to the previous line
int lastLine = layout.getLineForVertical(heightLimit) - 1;
// If the text would not even fit on a single line, clear it
if (lastLine < 0) {
setText("");
}
// Otherwise, trim to the previous line and add an ellipsis
else {
int start = layout.getLineStart(lastLine);
int end = layout.getLineEnd(lastLine);
float lineWidth = layout.getLineWidth(lastLine);
float ellipseWidth = textPaint.measureText(mEllipsis);
// Trim characters off until we have enough room to draw the ellipsis
while (widthLimit < lineWidth + ellipseWidth) {
lineWidth = textPaint.measureText(text.subSequence(start, --end + 1).toString());
}
setText(text.subSequence(0, end) + mEllipsis);
}
}
}
// Some devices try to auto adjust line spacing, so force default line spacing
// and invalidate the layout as a side effect
setTextSize(TypedValue.COMPLEX_UNIT_PX, targetTextSize);
setLineSpacing(mSpacingAdd, mSpacingMult);
// Notify the listener if registered
if (mTextResizeListener != null) {
mTextResizeListener.onTextResize(this, currentTextSize, targetTextSize);
}
// Reset force resize flag
mNeedsResize = false;
}
// Set the text size of the text paint object and use a static layout to render text off screen before measuring
private int getTextHeight(CharSequence source, TextPaint paint, int width, float textSize) {
// modified: make a copy of the original TextPaint object for measuring
// (apparently the object gets modified while measuring, see also the
// docs for TextView.getPaint() (which states to access it read-only)
TextPaint paintCopy = new TextPaint(paint);
// Update the text paint object
paintCopy.setTextSize(textSize);
// Measure using a static layout
StaticLayout layout = new StaticLayout(source, paintCopy, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
return layout.getHeight();
}
}