Android TextView多文本折叠展开 Android TextView多文本折叠展开效果

时间:2021-03-22 kuaizilanqiu 人气:0

想了解Android TextView多文本折叠展开效果的相关内容吗，kuaizilanqiu在本文为您仔细讲解Android TextView多文本折叠展开的相关知识和一些Code实例，欢迎阅读和指正，我们先划重点：Android,TextView多文本折叠展开,TextView多文本折叠展开,Android多文本折叠展开，下面大家一起来学习吧。

最近做项目，效果图要用到TextView的折叠，超过一定行数的时候，就会折叠起来，点击可以展开。网上找了一些效果，自己也稍作了修改。便拿来与网友分享分享。
参考文献：Android UI实现多行文本折叠展开效果

第一种：通过多个布局组合实现
大概步骤：
- 定义布局，垂直的线性LinearLayout布局、TextView和ImageView。在layout中定义基本组件。
- 设置TextView的高度为指定行数*行高。不使用maxLine的原因是maxLine会控制显示文本的行数，不方便后边使用动画展开全部内容。因此这里TextView的高度也因该为wrap_content。
- 给整个布局添加点击事件，绑定动画。点击时，若TextView未展开则展开至其实际高度，imageView 旋转；否则回缩至指定行数*行高 , imageView 旋转缩回。
布局文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:more="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/activity_main"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 tools:context="com.example.my.textviewdemotest.MainActivity">

 <TextView
 android:id="@+id/textView1"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:textColor="@android:color/black"
 android:textSize="18sp">
 </TextView>

 <RelativeLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content">

 <TextView
 android:id="@+id/expand_text"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:text="更多"
 android:textSize="18sp"
 android:visibility="gone"/>

 <ImageView
 android:id="@+id/expand_view1"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_alignParentRight="true"
 android:paddingBottom="5dip"
 android:paddingLeft="5dip"
 android:paddingRight="5dip"
 android:paddingTop="5dip"
 android:src="@drawable/ic_expand_more_red_700_24dp"
 android:visibility="gone"
 />
 </RelativeLayout>
 <!-- 第二种方法 -->
 <com.example.my.textviewdemotest.TextMoreTextView
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:ellipsize="end"
 more:maxLine="2"
 more:text="@string/text"
 more:textColor="@android:color/black"
 more:textSize="18dip">
 </com.example.my.textviewdemotest.TextMoreTextView>
</LinearLayout>

核心代码：

package com.example.my.textviewdemotest;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.RotateAnimation;
import android.view.animation.Transformation;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

 TextView text1;
 ImageView mImageView1;
 TextView expandText;
 //TextMoreTextView text2;

 boolean isExpand;//是否已展开的状态
 private int maxDescripLine = 3; //TextView默认最大展示行数
 private int deltaValue;//默认高度，即前边由maxLine确定的高度
 private int startValue;//起始高度
 private int durationMillis = 350;//动画持续时间

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 text1 = (TextView) findViewById(R.id.textView1);
 // text2= (TextMoreTextView) findViewById(R.id.text_textView);
 expandText = (TextView) findViewById(R.id.expand_text);

 mImageView1 = (ImageView) findViewById(R.id.expand_view1);
 mImageView1.setOnClickListener(this);

 text1.setText(getText(R.string.text));
 //第二种可以在这里直接设置文字
 // text2.setText(getText(R.string.text));
 //这里大家可以根据实际情况来设置文字的高度，做个判断（可能会文字只有一行，也会占据maxDescripLine行）
 text1.setHeight(text1.getLineHeight() * maxDescripLine);
 text1.post(new Runnable() {
 @Override
 public void run() {
 mImageView1.setVisibility(text1.getLineCount() > maxDescripLine ? View.VISIBLE : View.GONE);
 expandText.setVisibility(text1.getLineCount() > maxDescripLine ? View.VISIBLE : View.GONE);
 }
 });
 }

 @Override
 public void onClick(View v) {
 switch (v.getId()) {
 case R.id.expand_view1:
 zheDie(text1, mImageView1);
 break;
 }

 }

 private void zheDie(final TextView text, ImageView imageView) {
 isExpand = !isExpand;
 text.clearAnimation();
 startValue = text.getHeight();
 if (isExpand) {
 /**
 * 折叠动画
 * 从实际高度缩回起始高度
 */
 deltaValue = text.getLineHeight() * text.getLineCount() - startValue;
 RotateAnimation animation = new RotateAnimation(0, 180, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
 animation.setDuration(durationMillis);
 animation.setFillAfter(true);
 imageView.startAnimation(animation);
 expandText.setText("收起");
 } else {
 /**
 * 展开动画
 * 从起始高度增长至实际高度
 */
 deltaValue = text.getLineHeight() * maxDescripLine - startValue;
 RotateAnimation animation = new RotateAnimation(180, 0, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
 animation.setDuration(durationMillis);
 animation.setFillAfter(true);
 imageView.startAnimation(animation);
 expandText.setText("更多");
 }
 Animation animation = new Animation() {
 protected void applyTransformation(float interpolatedTime, Transformation t) { //根据ImageView旋转动画的百分比来显示textview高度，达到动画效果
 text.setHeight((int) (startValue + deltaValue * interpolatedTime));
 }
 };
 animation.setDuration(durationMillis);
 text.startAnimation(animation);
 }
}

第二种方法，如果用的地方多可以省去很多冗余代码：具体步骤就不直接分析。
核心代码：

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="MoreTextStyle">
 <attr name="textSize" format="dimension"/>
 <attr name="textColor" format="color"/>
 <attr name="maxLine" format="integer" />
 <attr name="text" format="string" />
 </declare-styleable>
</resources>

package com.example.my.textviewdemotest;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Color;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.ViewTreeObserver;
import android.view.animation.Animation;
import android.view.animation.RotateAnimation;
import android.view.animation.Transformation;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class TextMoreTextView extends LinearLayout {
 protected TextView contentView;
 protected ImageView expandView;

 protected int textColor;
 protected float textSize;
 protected int maxLine;
 protected String text;

 public int defaultTextColor = Color.BLACK;//默认文字颜色
 public int defaultTextSize = 12; //默认文字大小
 public int defaultLine = 3; //默认行数

 public TextMoreTextView(Context context, AttributeSet attrs) {
 super(context, attrs);
 initalize();
 initWithAttrs(context, attrs);
 // bindListener();
 }

 protected void initWithAttrs(Context context, AttributeSet attrs) {
 TypedArray a = context.obtainStyledAttributes(attrs,
 R.styleable.MoreTextStyle);
 int textColor = a.getColor(R.styleable.MoreTextStyle_textColor,
 defaultTextColor);
 textSize = a.getDimensionPixelSize(R.styleable.MoreTextStyle_textSize, defaultTextSize);
 maxLine = a.getInt(R.styleable.MoreTextStyle_maxLine, defaultLine);
 text = a.getString(R.styleable.MoreTextStyle_text);
 bindTextView(textColor, textSize, maxLine, text);
 a.recycle();
 }

 protected void initalize() {
 setOrientation(VERTICAL);
 setGravity(Gravity.RIGHT);
 contentView = new TextView(getContext());
 addView(contentView, LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
 expandView = new ImageView(getContext());
 int padding = dip2px(getContext(), 5);
 expandView.setPadding(padding, padding, padding, padding);
 expandView.setImageResource(R.drawable.ic_expand_more_red_700_24dp);
 LayoutParams llp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
 addView(expandView, llp);
 }

 protected void bindTextView(int color, float size, final int line, String text) {
 contentView.setTextColor(color);
 contentView.setTextSize(TypedValue.COMPLEX_UNIT_PX, size);
 contentView.setText(text);
 ViewTreeObserver observer = contentView.getViewTreeObserver();
 observer.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
 //判断写在这个方法里面能拿到contentView.getLineCount()，否则返回时0；
 @Override
 public void onGlobalLayout() {
 ViewTreeObserver obs = contentView.getViewTreeObserver();
 obs.removeGlobalOnLayoutListener(this);
 if (contentView.getLineCount() < line) {
 contentView.setHeight(contentView.getLineHeight() * contentView.getLineCount());
 } else {
 contentView.setHeight(contentView.getLineHeight() * line);
 bindListener();//只有在行数大于设定行数才会执行这个方法，做了调整否则会有bug。
 }
 //Log.e("aaa", "bindTextView111: " + contentView.getLineCount());//返回0，为什么
 }
 });

 post(new Runnable() {
 @Override
 public void run() {
 expandView.setVisibility(contentView.getLineCount() > line ? View.VISIBLE : View.GONE);
 //Log.e("aaa", "run: "+contentView.getLineCount() );
 }
 });
 }

 protected void bindListener() {
 setOnClickListener(new OnClickListener() {
 boolean isExpand;

 @Override
 public void onClick(View v) {
 isExpand = !isExpand;
 contentView.clearAnimation();
 final int deltaValue;
 final int startValue = contentView.getHeight();
 int durationMillis = 350;
 if (isExpand) {
 deltaValue = contentView.getLineHeight() * contentView.getLineCount() - startValue;
 RotateAnimation animation = new RotateAnimation(0, 180, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
 animation.setDuration(durationMillis);
 animation.setFillAfter(true);
 expandView.startAnimation(animation);
 } else {
 deltaValue = contentView.getLineHeight() * maxLine - startValue;
 RotateAnimation animation = new RotateAnimation(180, 0, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
 animation.setDuration(durationMillis);
 animation.setFillAfter(true);
 expandView.startAnimation(animation);
 }
 Animation animation = new Animation() {
 protected void applyTransformation(float interpolatedTime, Transformation t) {
 contentView.setHeight((int) (startValue + deltaValue * interpolatedTime));
 }

 };
 animation.setDuration(durationMillis);
 contentView.startAnimation(animation);
 }
 });
 }

 public TextView getTextView() {
 return contentView;
 }

 public void setText(CharSequence charSequence) {
 contentView.setText(charSequence);
 }

 public static int dip2px(Context context, float dipValue) {
 final float scale = context.getResources().getDisplayMetrics().density;
 return (int) (dipValue * scale + 0.5f);
 }
}

这个类这样就写好了。调用直接在布局文件中引用就行了。

源码下载：http://xiazai.jb51.net/201610/yuanma/Androidtextview(jb51.net).rar

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