Android編程之仿微信顯示更多文字的View

朋友圈中，如果好友發表的文字過長，會自動收縮起來，底下有提示，當點擊“顯示更多”時才會展開。

 

首先定義布局檔案（很簡單，不解釋）：

<?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> <?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" />

 
文字：

 string name="desc_shrinkup">收合</string> <string name="desc_spread">顯示更多</string>     <string name="desc_shrinkup">收合</string>    <string name="desc_spread">顯示更多</string>

接下來就是對文字的處理，原理就是設定TextView最大行數。

先判斷文字是否超過了規定的行數，如果沒超過，不顯現“顯示更多”的文字提示。當文字超過了，就顯示“顯示更多”的文字提示。使用者點擊“顯示更多”後，設定最大行數為最大。

補一句：的預設最大行數是10行，我這裡設定是2行。你可以自行設定該值DEFAULT_MAX_LINE_COUNT。

 

代碼如下：

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;             }         }     } } 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;            }        }    }}