Android编程之仿微信显示更多文字的View

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微信朋友圈中,如果好友发表的文字过长,会自动收缩起来,底下有提示,当点击“显示更多”时才会展开。

 

首先定义布局文件(很简单,不解释):

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >    <TextView        android:id="@+id/desc_tv"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginTop="4.0dip"        android:gravity="center_vertical"        android:textColor="#ff000000"        android:textSize="14.0dip" />    <TextView        android:id="@+id/desc_op_tv"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginTop="4.0dip"        android:gravity="center"        android:singleLine="true"        android:textColor="#ff576b95"        android:textSize="14.0dip"        android:visibility="gone" /></LinearLayout>

 

文字:

    <string name="desc_shrinkup">收起</string>    <string name="desc_spread">显示更多</string>


 

接下来就是对文字的处理,原理就是设置TextView最大行数。

先判断文字是否超过了规定的行数,如果没超过,不显现“显示更多”的文字提示。当文字超过了,就显示“显示更多”的文字提示。用户点击“显示更多”后,设置最大行数为最大。

补一句:微信的默认最大行数是10行,我这里设置是2行。你可以自行设置该值DEFAULT_MAX_LINE_COUNT。

 

代码如下:

public class CollapsibleTextView extends LinearLayout implements        OnClickListener {    /** default text show max lines */    private static final int DEFAULT_MAX_LINE_COUNT = 2;    private static final int COLLAPSIBLE_STATE_NONE = 0;    private static final int COLLAPSIBLE_STATE_SHRINKUP = 1;    private static final int COLLAPSIBLE_STATE_SPREAD = 2;    private TextView desc;    private TextView descOp;    private String shrinkup;    private String spread;    private int mState;    private boolean flag;    public CollapsibleTextView(Context context, AttributeSet attrs) {        super(context, attrs);        shrinkup = context.getString(R.string.desc_shrinkup);        spread = context.getString(R.string.desc_spread);        View view = inflate(context, R.layout.collapsible_textview, this);        view.setPadding(0, -1, 0, 0);        desc = (TextView) view.findViewById(R.id.desc_tv);        descOp = (TextView) view.findViewById(R.id.desc_op_tv);        descOp.setOnClickListener(this);    }    public CollapsibleTextView(Context context) {        this(context, null);    }    public final void setDesc(CharSequence charSequence, BufferType bufferType) {        desc.setText(charSequence, bufferType);        mState = COLLAPSIBLE_STATE_SPREAD;        requestLayout();    }    @Override    public void onClick(View v) {        flag = false;        requestLayout();    }    @Override    protected void onLayout(boolean changed, int l, int t, int r, int b) {        super.onLayout(changed, l, t, r, b);        if (!flag) {            flag = true;            if (desc.getLineCount() <= DEFAULT_MAX_LINE_COUNT) {                mState = COLLAPSIBLE_STATE_NONE;                descOp.setVisibility(View.GONE);                desc.setMaxLines(DEFAULT_MAX_LINE_COUNT + 1);            } else {                post(new InnerRunnable());            }        }    }    class InnerRunnable implements Runnable {        @Override        public void run() {            if (mState == COLLAPSIBLE_STATE_SPREAD) {                desc.setMaxLines(DEFAULT_MAX_LINE_COUNT);                descOp.setVisibility(View.VISIBLE);                descOp.setText(spread);                mState = COLLAPSIBLE_STATE_SHRINKUP;            } else if (mState == COLLAPSIBLE_STATE_SHRINKUP) {                desc.setMaxLines(Integer.MAX_VALUE);                descOp.setVisibility(View.VISIBLE);                descOp.setText(shrinkup);                mState = COLLAPSIBLE_STATE_SPREAD;            }        }    }}


 

效果图:

 

 

 

 

代码工程:

http://download.csdn.net/detail/xyz_fly/5625783