微信朋友圈中,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。
首先定義佈局文件(很簡單,不解釋):
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://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="https://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">收起</string> <string name="desc_spread">顯示更多</string> <string name="desc_shrinkup">收起</string> <string name="desc_spread">顯示更多</string>
接下來就是對文字的處理,原理就是設置TextView最大行數。
先判斷文字是否超過瞭規定的行數,如果沒超過,不顯現“顯示更多”的文字提示。當文字超過瞭,就顯示“顯示更多”的文字提示。用戶點擊“顯示更多”後,設置最大行數為最大。
補一句:微信的默認最大行數是10行,我這裡設置是2行。你可以自行設置該值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; } } } }