Align top of image to top of TextView

问题:

I want to create a layout that aligns the top of an image to the top of a TextView like this:

---------  Text text text text text text text
| Image |  text text text text text text text
---------  text text text text text text text
           text text text text text text text
           text text text text text.

I tried doing this by setting android:drawableLeft to my image, but that centers the image vertically:

           Text text text text text text text
---------  text text text text text text text
| Image |  text text text text text text text
---------  text text text text text text text
           text text text text text.

Is this possible with just a TextView or do I need to create a RelativeLayout containing a TextView and an ImageView?

Here is the XML layout for my TextView that gives the incorrect layout:

<TextView
    android:gravity="top"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:drawableLeft="@drawable/image"
    android:drawablePadding="8dp"
    android:text="@string/text" />

The android:gravity="top" attribute only seems to affect the text, not the drawable.

回答1:

You can align a compound-Drawable to the top (or bottom) by creating a custom Drawable that wraps your Drawable, and then manipulate the drawing of your custom Drawable by overriding the method onDraw(Canvas).

The sample below is the simplest possible example. This aligns the image to the top, but you can also make it align to the bottom, left or right of the TextView by implementing the required logic in the onDraw(Canvas)-method. You might also want to build in a margin in the onDraw(Canvas), to make your design implementation pixel perfect.

Sample usage:

GravityCompoundDrawable gravityDrawable = new GravityCompoundDrawable(innerDrawable);
// NOTE: next 2 lines are important!
innerDrawable.setBounds(0, 0, innerDrawable.getIntrinsicWidth(), innerDrawable.getIntrinsicHeight());
gravityDrawable.setBounds(0, 0, innerDrawable.getIntrinsicWidth(), innerDrawable.getIntrinsicHeight());
mTextView.setCompoundDrawables(gravityDrawable, null, null, null);

Sample code:

public class GravityCompoundDrawable extends Drawable {

    // inner Drawable
    private final Drawable mDrawable;

    public GravityCompoundDrawable(Drawable drawable) {
        mDrawable = drawable;
    }

    @Override
    public int getIntrinsicWidth() {
        return mDrawable.getIntrinsicWidth();
    }

    @Override
    public int getIntrinsicHeight() {
        return mDrawable.getIntrinsicHeight();
    }

    @Override
    public void draw(Canvas canvas) {
        int halfCanvas= canvas.getHeight() / 2;
        int halfDrawable = mDrawable.getIntrinsicHeight() / 2;

        // align to top
        canvas.save();
        canvas.translate(0, -halfCanvas + halfDrawable);
        mDrawable.draw(canvas);
        canvas.restore();
    }
}

回答2:

Try to USe RelativeLayout......

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/imageView1"
        android:text="@string/text" />

</RelativeLayout>

回答3:

I think, there's an easier and faster way than have 3 views. You need to prepare proper 9patch for icon and then use FrameLayout. It's even possible to have only single EditText / TextView using the same drawable as their background. More details are described in this answer.

回答4:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@+id/imageView1"
        android:text="@string/text" />

</RelativeLayout>

This would do it.

回答5:

Use layout_alignTop. With it you can align the top of the view to the top of another view

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/text" />

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@id/textView1"
        android:layout_toLeftOf="@id/textView1"
        android:src="@drawable/ic_launcher" />    

</RelativeLayout>