Android 开发 Tip 11 -- TabLayout 设置文字大小一致

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转载请注明出处：http://blog.csdn.net/crazy1235/article/details/71425135

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使用TabLayout的时候，有些tab的文字比较多时，会出现与其他tab的文字大小不一致的情况！

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TabLayout 继承自 HorizontalScrollView

内部有几个关键的类：

• SlidingTabStrip – TabLayout的唯一子View

• Tab – 子item的实体类，包含text, icon, customView等属性

• TabView – 每个Tab的布局

• ViewPagerOnTabSelectedListener – – 监听滑动

• TabLayoutOnPageChangeListener – 监听滑动

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关于每个tab的文字大小的设置关键代码就在 TabView.onMeasure() 之中！

@Override        public void onMeasure(final int origWidthMeasureSpec, final int origHeightMeasureSpec) {            // ...            // We need to switch the text size based on whether the text is spanning 2 lines or not            if (mTextView != null) {                final Resources res = getResources();                float textSize = mTabTextSize;                int maxLines = mDefaultMaxLines;                if (mIconView != null && mIconView.getVisibility() == VISIBLE) {                    // If the icon view is being displayed, we limit the text to 1 line                    maxLines = 1;                } else if (mTextView != null && mTextView.getLineCount() > 1) {                    // Otherwise when we have text which wraps we reduce the text size                    textSize = mTabTextMultiLineSize;                }                final float curTextSize = mTextView.getTextSize();                final int curLineCount = mTextView.getLineCount();                final int curMaxLines = TextViewCompat.getMaxLines(mTextView);                if (textSize != curTextSize || (curMaxLines >= 0 && maxLines != curMaxLines)) {                    // We've got a new text size and/or max lines...                    boolean updateTextView = true;                    if (mMode == MODE_FIXED && textSize > curTextSize && curLineCount == 1) {                        // If we're in fixed mode, going up in text size and currently have 1 line                        // then it's very easy to get into an infinite recursion.                        // To combat that we check to see if the change in text size                        // will cause a line count change. If so, abort the size change and stick                        // to the smaller size.                        final Layout layout = mTextView.getLayout();                        if (layout == null || approximateLineWidth(layout, 0, textSize)                                > getMeasuredWidth() - getPaddingLeft() - getPaddingRight()) {                            updateTextView = false;                        }                    }                    if (updateTextView) {                        mTextView.setTextSize(TypedValue.COMPLEX_UNIT_PX, textSize);                        mTextView.setMaxLines(maxLines);                        super.onMeasure(widthMeasureSpec, heightMeasureSpec);                    }                }            }        }

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TabLayout内部设置了两种字体大小：

float mTabTextSize;float mTabTextMultiLineSize;

final TypedArray ta = context.obtainStyledAttributes(mTabTextAppearance,                android.support.v7.appcompat.R.styleable.TextAppearance);        try {            mTabTextSize = ta.getDimensionPixelSize(                    android.support.v7.appcompat.R.styleable.TextAppearance_android_textSize, 0);            mTabTextColors = ta.getColorStateList(                    android.support.v7.appcompat.R.styleable.TextAppearance_android_textColor);        } finally {            ta.recycle();        }

<style name="TextAppearance.Design.Tab" parent="TextAppearance.AppCompat.Button">        <item name="android:textSize">@dimen/design_tab_text_size</item>        <item name="android:textColor">?android:textColorSecondary</item>        <item name="textAllCaps">true</item></style>

<dimen name="design_tab_text_size">14sp</dimen>

默认字体大小是14sp

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final Resources res = getResources();mTabTextMultiLineSize = res.getDimensionPixelSize(R.dimen.design_tab_text_size_2line);

<dimen name="design_tab_text_size_2line">12sp</dimen>

多行时字体大小为12sp

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结合onMeasure()来分析！

若使字体大小保持一致，一种方式是修改 mTabTextSize 这个默认字体大小；另外一种方式就是修改 mTabTextMultiLineSize 这个字体大小！

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方式一：

定义一个style，把默认字体大小设置成12sp！

<style name="TextAppearance.Design.Tab.Custom" parent="TextAppearance.AppCompat.Button">        <item name="android:textSize">12sp</item>        <item name="android:textColor">?android:textColorSecondary</item>        <item name="textAllCaps">true</item>    </style>

在TabLaout中引用

<android.support.design.widget.TabLayout            android:id="@+id/tab_layout"            android:layout_width="match_parent"            android:layout_height="wrap_content"            app:tabTextAppearance="@style/TextAppearance.Design.Tab.Custom"           />

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方式二：

把多行字体大小设置位于默认字体大小一致！

<dimen name="design_tab_text_size" tools:ignore="PrivateResource">14sp</dimen>