问题描述
我有以下布局的活动：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/testlayoutOverlays"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/testlayoutMain"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<RelativeLayout
android:id="@+id/testlayout_bottom"
android:layout_width="fill_parent"
android:layout_height="62dp"
android:background="#122334" >
<ImageView
android:id="@+id/testbtnBlock"
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_alignParentLeft="true"
android:layout_gravity="left|center_vertical"
android:contentDescription="Test1"
android:padding="@dimen/padding_medium"
android:src="@drawable/btnblock" />
<TextView
android:id="@+id/testtxtZoomPan"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toLeftOf="@+id/testbtnX"
android:layout_toRightOf="@+id/testbtnBlock"
android:gravity="center_horizontal"
android:text="@string/txtZoomPan"
android:textColor="#FFFFFF" />
<ImageView
android:id="@+id/testbtnX"
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_alignParentRight="true"
android:layout_gravity="right|center_vertical"
android:contentDescription="Test2"
android:padding="@dimen/padding_medium"
android:src="@drawable/btnx" />
</RelativeLayout>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/testlayoutPuzzleInfo"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="10dp"
android:orientation="horizontal" >
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/testlayoutChronoErrors"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<Chronometer
android:id="@+id/testchronometer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:format="@string/chronometer_initial_format"
android:gravity="center" />
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/testlayoutErrors"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<ImageView
android:layout_width="1px"
android:layout_height="20dp" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
</RelativeLayout>
和以下code：
package minmaxdev.android.picrossanywhere;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.support.v4.app.NavUtils;
public class TestActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
// Capture our button from layout
ImageView button = (ImageView) findViewById(R.id.testbtnBlock);
// Register the onClick listener with the implementation above
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
RelativeLayout rv = (RelativeLayout) findViewById(R.id.testlayoutOverlays);
rv.setGravity(Gravity.CENTER);
Button btnRetry = new Button(TestActivity.this);
btnRetry.setId(R.id.btnRetry);
btnRetry.setBackgroundResource(R.drawable.btnselector);
RelativeLayout.LayoutParams prmBtn = new RelativeLayout.LayoutParams(Util.DPsToPixels(200, getResources()), Util.DPsToPixels(40, getResources()));
prmBtn.setMargins(0, 120, 0, 0);
btnRetry.setLayoutParams(prmBtn);
// btnRetry.setGravity(Gravity.CENTER_HORIZONTAL);
btnRetry.setText("Retry");
btnRetry.setOnClickListener(new ImageView.OnClickListener() {
public void onClick(View v) {
Intent intent = getIntent();
finish();
startActivity(intent);
}
});
rv.addView(btnRetry);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_test, menu);
return true;
}
}
我想知道：为什么我的动态创建按钮（名为 btnRetry ）没有出现在屏幕中央，因为我设置父RelativeLayout的重力中心 RV。 setGravity（Gravity.CENTER）？
I would like to know :Why is my dynamically created Button (named btnRetry) not appearing in the center of the screen, since I set the parent RelativeLayout gravity to center with rv.setGravity(Gravity.CENTER) ?
非常感谢您的宝贵时间。
Thank you very much for your time
推荐答案
答案很简单。重力作品为内容，layout_gravity对于使用该视图。来源基本上是： http://stackoverflow.com/a/3482757/180538
The answer is easy. Gravity works for the content, layout_gravity for the view that uses that.Source basically: http://stackoverflow.com/a/3482757/180538
尝试使用LayoutParams与 addRule（RelativeLayout.CENTER_IN_PARENT，RelativeLayout.TRUE）;
要回答你的重力的理解：你是对的，但我想，在documentation重要的是：
To answer your gravity understanding: You are right but I guess that this information in the documentation is important:
请注意，由于RelativeLayout的考虑每个子相对于彼此的定位是显著，设定重力将影响所有儿童的定位作为父在一个单一的单元。出现这种情况的孩子已经相对定位后。
我不能在此刻测试你的布局，但我的猜测是，如果引力所施加的时间不会产生预期的结果。
I can't test your layout at the moment but my guess is that the time where gravity is applied doesn't create the expected result.
我个人利用重力只有在LinearLayouts和 centerInParent 的RelativeLayouts。
Personally I would use gravity only in LinearLayouts and the centerInParent for RelativeLayouts.
这篇关于RelativeLayout的比重没有应用？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！