Toast多行文字居中显示

最新推荐文章于 2024-08-09 09:26:54 发布

原创最新推荐文章于 2024-08-09 09:26:54 发布 · 6.1k 阅读

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CC 4.0 BY-SA版权

本文介绍如何使Android Toast消息中的文字在多行显示时居中对齐，并提供了一个Toast工具类示例，解决了多次调用Toast.makeText导致的文字重复显示问题。

Toast显示文字过多时，会拆分为多行靠左显示，如何实现在拆分多行时居中显示文字？

先来看看makeText方法

public static Toast makeText(Context context, CharSequence text, @Duration int duration) {
        Toast result = new Toast(context);

        LayoutInflater inflate = (LayoutInflater)
                context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View v = inflate.inflate(com.android.internal.R.layout.transient_notification, null);
        TextView tv = (TextView)v.findViewById(com.android.internal.R.id.message);
        tv.setText(text);
        
        result.mNextView = v;
        result.mDuration = duration;

        return result;
    }

可以知道makeText方法使用的布局文件是com.android.internal.R.layout.transient_notification

打开布局文件查看

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="?android:attr/toastFrameBackground">

    <TextView
        android:id="@android:id/message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:layout_gravity="center_horizontal"
        android:textAppearance="@style/TextAppearance.Toast"
        android:textColor="@color/bright_foreground_dark"
        android:shadowColor="#BB000000"
        android:shadowRadius="2.75"
        />

</LinearLayout>

可以知道显示文字的TextView的id名称是message，既然知道了id名称，通过Resources类就可以拿到这个TextView的id索引，进而通过findViewById拿到TextView后更改文字对齐属性

textview_id = Resources.getSystem().getIdentifier("message", "id", "android");
((TextView) toast.getView().findViewById(textview_id)).setGravity(Gravity.CENTER);

当然，你也可以更改其他属性，如字体颜色，大小等

这里附上自己用的Toast工具类，解决多次调用Toast.makeText时，重复显示文字问题

public class ToastUtil {

    private static Toast toast;
    private static int textview_id;

    public static void show(Context context, String str) {
        if (toast == null)
            toast = Toast.makeText(context.getApplicationContext(), str, Toast.LENGTH_SHORT);
        else
            toast.setText(str);
        if (textview_id == 0)
            textview_id = Resources.getSystem().getIdentifier("message", "id", "android");
        ((TextView) toast.getView().findViewById(textview_id)).setGravity(Gravity.CENTER);
        toast.show();
    }

    public static void show(Context context, int resId) {
        if (toast == null)
            toast = Toast.makeText(context.getApplicationContext(), resId, Toast.LENGTH_SHORT);
        else
            toast.setText(resId);
        if (textview_id == 0)
            textview_id = Resources.getSystem().getIdentifier("message", "id", "android");
        ((TextView) toast.getView().findViewById(textview_id)).setGravity(Gravity.CENTER);
        toast.show();
    }

}