[英]Prevent a multiline TextView from unnecessarily expanding to it's maximum width
擴展為多行的 TextView 似乎會自動擴展以適應其最大可能寬度。 我怎樣才能防止這種情況發生?
這是一個示例布局(test.xml)
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/white">
<TextView
android:background="@color/green"
android:layout_alignParentRight="true"
android:id="@+id/foo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="right"
android:text="This is the message a much shorter message"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textColor="@color/black" />
</RelativeLayout>
如果我在左側添加邊距,它會正確縮小 TextView 的寬度(不重新格式化內容),但邊距的大小必須根據 TextView 的內容計算。
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/white">
<TextView
android:layout_marginLeft="32dp"
android:background="@color/green"
android:layout_alignParentRight="true"
android:id="@+id/foo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="right"
android:text="This is the message a much shorter message"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textColor="@color/black" />
</RelativeLayout>
您可以在計算寬度的地方使用帶有覆蓋方法 onMeasure() 的自定義 TextView:
public class WrapWidthTextView extends TextView {
// ...
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
Layout layout = getLayout();
if (layout != null) {
int width = (int)FloatMath.ceil(getMaxLineWidth(layout))
+ getCompoundPaddingLeft() + getCompoundPaddingRight();
int height = getMeasuredHeight();
setMeasuredDimension(width, height);
}
}
private float getMaxLineWidth(Layout layout) {
float max_width = 0.0f;
int lines = layout.getLineCount();
for (int i = 0; i < lines; i++) {
if (layout.getLineWidth(i) > max_width) {
max_width = layout.getLineWidth(i);
}
}
return max_width;
}
}
如果您想使用@Vitaliy Polchuk 的建議(最佳答案),請重寫或查看他的答案, 為什么將內容包裝在多行 TextView 填充父項中? :
public class WrapWidthTextView extends AppCompatTextView {
public WrapWidthTextView(Context context) {
super(context);
}
public WrapWidthTextView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
}
public WrapWidthTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
Layout layout = getLayout();
if (layout != null) {
int width = (int) Math.ceil(getMaxLineWidth(layout))
+ getCompoundPaddingLeft() + getCompoundPaddingRight();
int height = getMeasuredHeight();
setMeasuredDimension(width, height);
}
}
private float getMaxLineWidth(Layout layout) {
float max_width = 0.0f;
int lines = layout.getLineCount();
for (int i = 0; i < lines; i++) {
if (layout.getLineWidth(i) > max_width) {
max_width = layout.getLineWidth(i);
}
}
return max_width;
}
}
將此類插入 XML 時重建項目。 否則它不會找到這個類。
我已經嘗試過Vitaliy Polchuk的解決方案,效果很好。 我還想添加一些小的更正:
...
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
Layout layout = getLayout();
if (layout != null) {
int width = (int) FloatMath.ceil(getMaxLineWidth(layout))
+ getCompoundPaddingLeft() + getCompoundPaddingRight();
widthMeasureSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY);
}
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
// get already measured dimensions
int width = getMeasuredWidth();
int height = getMeasuredHeight();
setMeasuredDimension(width, height);
}
...
使用android:padding="32dp"
它可以幫助你有填充,如果你想從左邊使用android:paddingLeft="32dp"
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