本文实例为大家分享了一个可以展开的TextView的具体代码，供大家参考，具体内容如下

原理是通过点击的时候设置 setMaxLines(lineNum)来实现:

public class ExpandableTextView extends TextView { private static int MIN_LINE_NUM = 2; private static int MAX_LINE_NUM = 20; private int lineNum = MIN_LINE_NUM; private boolean mIsExpanded = false; Bitmap bitmapDown; Bitmap bitmapUp; int w, h; /** 点击事件listener */ private OnClickListener mOnClickListener; public ExpandableTextView(Context context, AttributeSet attrs) { super(context, attrs); init(context, attrs); } private void init(Context context, AttributeSet attrs) { setMaxLines(lineNum); bitmapDown = BitmapFactory.decodeResource(getResources(), R.drawable.update_detail_down); bitmapUp = BitmapFactory.decodeResource(getResources(), R.drawable.update_detail_up); w = bitmapDown.getWidth() + (int) context.getResources().getDimension(R.dimen.expand_textview_right); h = bitmapDown.getHeight() + (int) context.getResources().getDimension(R.dimen.expand_textview_bottom); super.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { if (lineNum == MIN_LINE_NUM) { lineNum = MAX_LINE_NUM; setMaxLines(lineNum); } else { lineNum = MIN_LINE_NUM; setMaxLines(lineNum); } if (mOnClickListener != null) { mOnClickListener.onClick(v); } } }); } @Override public void setOnClickListener(OnClickListener listener) { if (!isClickable()) { setClickable(true); } mOnClickListener = listener; } @Override public void setMaxLines(int maxlines) { super.setMaxLines(maxlines); if (lineNum == MAX_LINE_NUM) { mIsExpanded = true; } else { mIsExpanded = false; } } public boolean isExpanded() { return mIsExpanded; } @Override protected void onDraw(Canvas canvas) { if (getLineCount() <= MIN_LINE_NUM) { super.onDraw(canvas); return; } if (lineNum == MIN_LINE_NUM) { canvas.drawBitmap(bitmapDown, getWidth() - w, getHeight() - h, null); } else { canvas.drawBitmap(bitmapUp, getWidth() - w, getHeight() - h, null); } super.onDraw(canvas); } public void setMaxLine(int line) { lineNum = line; setMaxLines(line); } }

这样来写Layout:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#FFFFFF" > <TextView android:id="@+id/detail_action" android:textColor="#000000" android:textSize="11sp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_marginRight="8dip" android:drawablePadding="4dip" android:paddingBottom="10dip" android:paddingTop="10dip" android:singleLine="true" android:text="sdfkljsfiosjdfiosfjsiofjsdifsd" /> <com.example.view.ExpandableTextView android:id="@+id/textview" android:layout_width="100dp" android:layout_height="wrap_content" android:layout_below="@id/detail_action" android:lineSpacingExtra="4dip" android:paddingBottom="-40dip" android:paddingRight="48dip" android:text="adfsfsfewrwerwerwerqRWgdffdfdfERSAFSDFSDFSDd" android:layout_marginTop="-5dip" android:textColor="#000000" > </com.example.view.ExpandableTextView> <TextView android:id="@+id/detail_action1" android:textColor="#000000" android:textSize="11sp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/textview" android:layout_marginRight="8dip" android:drawablePadding="4dip" android:paddingBottom="10dip" android:paddingTop="10dip" android:singleLine="true" android:text="sdfkljsfiosjdfiosfjsiofjsdifsd" /> </RelativeLayout>

效果图：

代码：一个可以展开的TextView

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。