Android开发教程实战案例源码分享-TextView超过多少行显示展开收起

Android开发教程实战案例源码分享-TextView超过多少行显示展开收起

就是TextView的展开收起功能

一、思路：

addOnGlobalLayoutListener里面算现在多少行了

二、效果图：

三、关键代码：

public class MoreTextView2 extends LinearLayout {
    /**
     * TextView的实际高度
     */
    private int textViewHeight;
    /**
     * 默认全文的Text
     */
    private static final String EXPANDEDTEXT = "全文";
    /**
     * 默认收起的text
     */
    private static final String COLLAPSEDTEXT = "收起";
    /**
     * 全文的text
     */
    private String expandedText;
    /**
     * 收起的text
     */
    private String collapsedText;
    /**
     * 字体大小
     */
    private int textSize;
    /**
     * 字体颜色
     */
    private int textColor;
    /**
     * 超过多少行出现全文、收起按钮
     */
    private int trimLines;
    /**
     * 显示文本的TextView
     */
    private TextView showTextView;
    /**
     * 全文和收起的TextView
     */
    private TextView collapseTextView;
    /**
     * 是否是收起状态，默认收起
     */
    private boolean collapsed = true;

    private boolean show;

    public MoreTextView2(Context context, AttributeSet attrs) {
        super(context, attrs);
        initView(context, attrs);
    }

    public MoreTextView2(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initView(context, attrs);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public MoreTextView2(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        initView(context, attrs);
    }

    private void initView(Context context, AttributeSet attrs) {
        showTextView = new TextView(context);
        setOrientation(VERTICAL);
        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.MoreTextView2);
        textColor = typedArray.getColor(R.styleable.MoreTextView2_textColor, Color.GRAY);
        textSize = typedArray.getDimensionPixelSize(R.styleable.MoreTextView2_textSize, 14);
        expandedText = typedArray.getString(R.styleable.MoreTextView2_expandedText);
        if (TextUtils.isEmpty(expandedText)) {
            expandedText = EXPANDEDTEXT;
        }
        collapsedText = typedArray.getString(R.styleable.MoreTextView2_collapsedText);
        if (TextUtils.isEmpty(collapsedText)) {
            collapsedText = COLLAPSEDTEXT;
        }
        trimLines = typedArray.getInt(R.styleable.MoreTextView2_trimLines, 0);
        typedArray.recycle();
        showTextView.setTextSize(textSize);
        showTextView.setTextColor(textColor);
        showTextView.setLineSpacing(3f, 1.2f);
        //hint(没有自我介绍内容时的默认显示)
        SpannableString ss = new SpannableString(getResources().getString(R.string.formal_tips));//定义hint的值
        AbsoluteSizeSpan ass = new AbsoluteSizeSpan(14, true);//设置字体大小 true表示单位是sp
        ss.setSpan(ass, 0, ss.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
        showTextView.setHint(new SpannedString(ss));
        showTextView.setHintTextColor(getResources().getColor(R.color.text_aaa));

        addView(showTextView);
    }


    public void setText(CharSequence text) {
        showTextView.setText(text);
        globalLayout();
        requestLayout();
        invalidate();
        sum();
    }

    /**
     * 获取控件实际高度，并设置最大行数
     */
    private void globalLayout() {
        showTextView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                if (textViewHeight == 0) {
                    textViewHeight = showTextView.getHeight();
                }

                ViewTreeObserver obs = showTextView.getViewTreeObserver();
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                    obs.removeOnGlobalLayoutListener(this);
                } else {
                    obs.removeGlobalOnLayoutListener(this);
                }
                show = true;
                sum();

            }
        });
    }

    private void sum() {
        if (showTextView == null || !show) {
            return;
        }
        int allLine = 0;
        if (showTextView.getLayout() != null) {
            allLine = showTextView.getLayout().getLineCount();
        }

//                //计算总行数
//                int allLine = allWidth / showTextView.getWidth();
//
//                if(allWidth % showTextView.getWidth() == 0){
//                    textViewHeight = showTextView.getLineHeight() * allLine;
//                }else{
//                    allLine ++;
//                    textViewHeight = showTextView.getLineHeight() * allLine;
//                }


        if (trimLines > 0 && trimLines < allLine) {
            //需要全文和收起
            if (collapsed) {
                showTextView.setHeight(showTextView.getLineHeight() * trimLines);
            }

            if (collapseTextView == null) {
                //全文和收起的textView
                collapseTextView = new TextView(getContext());
                collapseTextView.setTextSize(textSize);
                collapseTextView.setTextColor(getContext().getResources().getColor(R.color.c_main));
                collapseTextView.setText(expandedText);
                LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,
                        LayoutParams.WRAP_CONTENT, Gravity.RIGHT | Gravity.BOTTOM);
                lp.setMargins(0, 10, 0, 0);
                collapseTextView.setLayoutParams(lp);

                collapseTextView.setOnClickListener(collapseListener);
                addView(collapseTextView);
                collapsed = true;
            }

        } else {
            if (collapseTextView != null) {
                removeView(collapseTextView);
                collapseTextView = null;
            }
            showTextView.setHeight(showTextView.getLineHeight() * showTextView.getLineCount());
        }
    }

四、项目demo源码结构图：

有问题或者需要完整源码demo的可以看简介联系我，也可以私信我，我每天都看私信的