76 lines
2.6 KiB
Plaintext
76 lines
2.6 KiB
Plaintext
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page.title=Hello, RelativeLayout
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parent.title=Hello, Views
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parent.link=index.html
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@jd:body
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<p>A {@link android.widget.RelativeLayout} is a ViewGroup that allows you to layout child elements
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in positions relative to the parent or siblings elements.</p>
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<ol>
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<li>Start a new project/Activity called HelloRelativeLayout.</li>
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<li>Open the layout file. Make it like so:
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<pre>
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<?xml version="1.0" encoding="utf-8"?>
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<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
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android:layout_width="fill_parent"
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android:layout_height="fill_parent">
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<TextView
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android:id="@+id/label"
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android:layout_width="fill_parent"
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android:layout_height="wrap_content"
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android:text="Type here:"/>
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<EditText
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android:id="@+id/entry"
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android:layout_width="fill_parent"
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android:layout_height="wrap_content"
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android:background="@android:drawable/editbox_background"
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android:layout_below="@id/label"/>
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<Button
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android:id="@+id/ok"
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android:layout_width="wrap_content"
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android:layout_height="wrap_content"
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android:layout_below="@id/entry"
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android:layout_alignParentRight="true"
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android:layout_marginLeft="10dip"
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android:text="OK" />
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<Button
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android:layout_width="wrap_content"
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android:layout_height="wrap_content"
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android:layout_toLeftOf="@id/ok"
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android:layout_alignTop="@id/ok"
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android:text="Cancel" />
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</RelativeLayout>
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</pre>
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<p>Pay attention to each of the additional <code>layout_*</code> attributes (besides the
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usual width and height, which are required for all elements). When using relative layout,
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we use attributes like <code>layout_below</code> and <code>layout_toLeftOf</code> to describe
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how we'd like to position each View. Naturally, these are different relative positions, and the
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value of the attribute is the id of the element we want the position relative to.</p>
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</li>
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<li>Make sure your Activity loads this layout in the <code>onCreate()</code> method:</p>
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<pre>
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public void onCreate(Bundle savedInstanceState) {
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super.onCreate(savedInstanceState);
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setContentView(R.layout.main);
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}
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</pre>
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<p><code>R.layout.main</code> refers to the <code>main.xml</code> layout file.</p>
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</li>
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<li>Run it.</li>
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</ol>
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<p>You should see the following:</p>
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<img src="images/hello-relativelayout.png" width="150px" />
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<h3>Resources</h3>
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<ul>
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<li>{@link android.widget.RelativeLayout}</li>
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<li>{@link android.widget.TextView}</li>
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<li>{@link android.widget.EditText}</li>
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<li>{@link android.widget.Button}</li>
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</ul>
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