如何在android中仅扩展textview

Question

我正在尝试在 android 中扩展 textview，我有一些带有批量内容的 textview，我的要求是仅显示批量内容中的两行并完成 (...)。如果我点击它，我的全部内容将不得不显示。如何 实现这一目标。你能帮帮我吗？

public class MainActivity extends ActionBarActivity {       
TextView t1;
@Override
protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);  
   t1 = (TextView) findViewById(R.id.text);
   String str = "If your view subclass is displaying its own Drawable objects, it should override this function and return true for any Drawable it is displaying. This allows animations for those drawables to be scheduled." +
                "I made the expandable list view acc to your tutorial but what i have to do if I want to populate Expandable List View with values from database?Means what changes I have to do in ";
    t1.setText(str);                               
    t1.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        t1.setMaxLines(Integer.MAX_VALUE);
    }
 });
}
}

Answer 1

您可以在布局xml中将textview的android:maxLines属性默认设置为2..

在将文本设置为 textview (t1) 后，在 onCreate() 函数中。
添加以下内容

 boolean isTextViewClicked = false;

t1.setOnClickListener(new OnClickListener() {
    if(isTextViewClicked){
      //This will shrink textview to 2 lines if it is expanded.
       t1.setmaxLines(2);
       isTextViewClicked = false;
    } else {
       //This will expand the textview if it is of 2 lines
       t1.setMaxLines(Integer.MAX_VALUE);
       isTextViewClicked = true;
    }
});

这将根据内容展开文本视图

Answer 2

我在medium article 中描述了最佳和优化方法。

您需要做的是在 TextView.post{} 函数中运行以下函数：

private fun TextView.setCaption(senderName: String, caption: String) {
    text = getFullCaption(senderName, caption)

    if (lineCount > DEFAULT_LINES) {
        val lastCharShown = layout.getLineVisibleEnd(DEFAULT_LINES - 1)
        maxLines = DEFAULT_LINES
        val moreString = context.getString(R.string.read_more)
        val suffix = " $moreString"
        // 3 is a "magic number" but it's just basically the length of the ellipsis we're going to insert
        val actionDisplayText = context.getString(R.string.more_dots) + suffix

        text = SpannableStringBuilder()
            .bold { append(senderName) }
            .append("  ")
            .append(
                caption.substring(
                    0,
                    lastCharShown - suffix.length - 3 - moreString.length - senderName.length
                )
            )
            .color(Color.GRAY) { append(actionDisplayText) }
    }
}

在 TextView 的扩展函数中调用 setCapton 函数并设置点击监听器使其展开，是拥有可展开 TextView 的最后一步：

private fun TextView.setExpandableText(senderName: String, caption: String) {
    post {
        setCaption(senderName, caption)
        setOnClickListener {
            let {
                it.maxLines = MAX_LINES
                it.text = getFullCaption(senderName, caption)
            }
        }
    }
}