如何在屏幕中央设置android进度栏

Question

I am trying to show the progress bar in the center of the screen, but it doesn't show up in the center. Below is my layout. What am i doing wrong here? Basically this is a layout to show image and android gallery widget on top. When the user clicks on the thumbnails, I am loading an image from the web and I want to show the progress dialog while the image is loading.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:ads="http://schemas.android.com/apk/lib/com.google.ads"
    android:id="@+id/container" android:layout_width="fill_parent"
    android:layout_height="fill_parent" android:orientation="vertical">

    <Gallery android:id="@+id/gallery" android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:gravity="top" />

    <ImageView android:id="@+id/actualimage" android:scaleType="fitCenter"
        android:layout_width="fill_parent" android:layout_height="wrap_content"
        android:visibility="gone" android:layout_gravity="center_vertical|center_horizontal|center"
        android:adjustViewBounds="true" />

    <ProgressBar android:id="@+android:id/progress_small1"
        android:layout_height="wrap_content" android:layout_width="wrap_content"
        android:visibility="visible" android:layout_gravity="center_vertical|center_horizontal"
        android:gravity="center_vertical|center_horizontal" />

</LinearLayout>

Answer 1

Using a LinearLayout will stack your views vertically. Right now, your ImageView and ProgressBar are fighting for the centered position. For this type of situation, I would definitely recommend a RelativeLayout .

With RelativeLayout , you use android:layout_centerInParent="true" .

Answer 2

Do android:gravity="center" in the root LinearLayout . Set the android:visibility of all other elements apart from the ProgressBar to gone when you want to show the ProgressBar

Answer 3

Add following:

android:layout_centerHorizontal="true"
android:layout_centerVertical="true"

Answer 4

Maybe you should go for progress dialog, since I believe you are trying to show a progress indicator until the images are loaded for the gallery.

This will get you started.

http://www.helloandroid.com/tutorials/using-threads-and-progressdialog

http://www.androidpeople.com/android-progress-dialog-example

And still if you are looking for a way to make use of your progressbar itself then maybe you should give a try to the answer provided by Bradley Uffner

Answer 5

尝试将进度条的layout_weight设置为1

Answer 6

I know this question is answered, but considering performance of laying out views/Subviews, RelativeLayout is expensive(it requires two pass). If your view hierarchy is complex, go for Relative Layout, or if your view has just simple views like below please go for Linear layout/Frame layout.

From my experience, when my app grown, UI performance with Relative layout was worse, ended up in reworking on all layout files :( Below is sample for putting a view(ProgressView in my case) in exactly center of view.

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent" android:orientation="vertical">
    <android.support.v7.widget.AppCompatImageView android:layout_gravity="center"  android:layout_width="match_parent"
        android:layout_height="0dp" app:srcCompat="@drawable/check" android:scaleType="fitCenter"
        android:layout_weight=".7"/>
    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="0dp" android:layout_weight=".3">
        <ProgressBar android:layout_gravity="center|center_horizontal" android:indeterminateTint="@color/textColorPrimary"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" android:indeterminate="true"/>
    </FrameLayout>

</LinearLayout>