关于实行textview 显示多行更多

最新推荐文章于 2023-07-03 14:10:13 发布

代码s贝多芬的音符

最新推荐文章于 2023-07-03 14:10:13 发布

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分类专栏： android高级文章标签： import layout string float interface null

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本文介绍了一种自定义Android TextView的实现方式，该View能够根据最大行数限制文本，并使用特定符号进行省略处理。通过重写TextView的关键方法，确保文本在限定行数内展示，同时支持监听省略状态变化。

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package cn.com.aisat.huawei.view;
import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.graphics.Canvas;
import android.text.Layout;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextUtils.TruncateAt;
import android.util.AttributeSet;
import android.widget.TextView;
import android.text.Layout;
import android.text.TextUtils.TruncateAt;

public class EllipsizingTextView extends TextView {

private static final String ELLIPSIS = "......";

public interface EllipsizeListener {
void ellipsizeStateChanged(boolean ellipsized);
}

private final List<EllipsizeListener> ellipsizeListeners = new ArrayList<EllipsizeListener>();

private boolean isEllipsized;
private boolean isStale;
private boolean programmaticChange;
private String fullText;
private int maxLines = -1;
private float lineSpacingMultiplier = 1.0f;
private float lineAdditionalVerticalPadding = 0.0f;

public EllipsizingTextView(Context context) {
super(context);
}

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

public EllipsizingTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}

public void addEllipsizeListener(EllipsizeListener listener) {
if (listener == null) {
throw new NullPointerException();
}
ellipsizeListeners.add(listener);
}

public void removeEllipsizeListener(EllipsizeListener listener) {
ellipsizeListeners.remove(listener);
}

public boolean isEllipsized() {
return isEllipsized;
}

@Override
public void setMaxLines(int maxLines) {
super.setMaxLines(maxLines);
this.maxLines = maxLines;
isStale = true;
}

public int getMaxLines() {
return maxLines;
}

@Override
public void setLineSpacing(float add, float mult) {
this.lineAdditionalVerticalPadding = add;
this.lineSpacingMultiplier = mult;
super.setLineSpacing(add, mult);
}

@Override
protected void onTextChanged(CharSequence text, int start, int before,
int after) {
super.onTextChanged(text, start, before, after);
if (!programmaticChange) {
fullText = text.toString();
isStale = true;
}
}

@Override
protected void onDraw(Canvas canvas) {
if (isStale) {
super.setEllipsize(null);
resetText();
}
super.onDraw(canvas);
}

private void resetText() {
int maxLines = getMaxLines();
String workingText = fullText;
boolean ellipsized = false;
if (maxLines != -1) {
Layout layout = createWorkingLayout(workingText);
if (layout.getLineCount() > maxLines) {

System.out.println(layout.getLineCount() + "\t" + maxLines);
workingText = fullText.substring(0,
layout.getLineEnd(maxLines - 1)).trim();
Layout layout2 = createWorkingLayout(workingText + ELLIPSIS);
while (layout2.getLineCount() > maxLines) {
System.out
.println(layout2.getLineCount() + "\t" + maxLines);
int lastSpace = workingText.lastIndexOf(' ');
System.out.println(lastSpace);
if (lastSpace == -1) {
break;
}
workingText = workingText.substring(0, lastSpace);
}
workingText = workingText + ELLIPSIS;
ellipsized = true;
}
}
if (!workingText.equals(getText())) {
programmaticChange = true;
try {
setText(workingText);
} finally {
programmaticChange = false;
}
}
isStale = false;
if (ellipsized != isEllipsized) {
isEllipsized = ellipsized;
for (EllipsizeListener listener : ellipsizeListeners) {
listener.ellipsizeStateChanged(ellipsized);
}
}
}

private Layout createWorkingLayout(String workingText) {
return new StaticLayout(workingText, getPaint(), getWidth()
- getPaddingLeft() - getPaddingRight(), Alignment.ALIGN_NORMAL,
lineSpacingMultiplier, lineAdditionalVerticalPadding, false);
}

@Override
public void setEllipsize(TruncateAt where) {
// Ellipsize settings are not respected } }
}
}