本文主要介绍LinearLayout中的两个属性
android:baselineAligned 和android:baselineAlignedChildIndex
1.android:baselineAligned
1.这个baseline指的是这个UI控件的baseline–文字距UI控件顶部的偏移量
2.只有带文本内容的控件才有基线,如TextView/Button/EditText
3.LinearLayout控件默认android:baselineAligned为true,如果
LinearLayout的orientation为horizontal的话,子控件默认是文字对齐的
2.android:baselineAlignedChildIndex
设置当前LinearLayout与其它View的对齐方式.
索引号从0开始,表示是以当前LinearLayout下第m+1控件为基准线与其它View对齐
3.效果图
4.布局文件
res/layout/fragment_base_line.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:id="@+id/ll_parent"
android:layout_width="match_parent"
android:layout_height="200dp"
android:baselineAligned="true"
android:baselineAlignedChildIndex="3"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="60dp"
android:layout_marginRight="3dip"
android:gravity="center"
android:text="String1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="3dip"
android:text="Button1"/>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:baselineAlignedChildIndex="1"
android:orientation="vertical">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@android:drawable/arrow_up_float"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dip"
android:text="String2"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@android:drawable/arrow_down_float"/>
</LinearLayout>
<LinearLayout
android:id="@+id/ll_child"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:baselineAlignedChildIndex="0"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dip"
android:text="String3"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@android:drawable/arrow_up_float"/>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@android:drawable/arrow_down_float"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dip"
android:text="String4"/>
</LinearLayout>
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="String5"
android:textSize="30dp"
/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp">
<ToggleButton
android:id="@+id/toggleButton1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textOn="baselineAligned_true"
android:textOff="baselineAligned_false"
android:checked="true"
android:onClick="click"/>
<ToggleButton
android:id="@+id/toggleButton2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:textOn="Baseline_String4"
android:textOff="Baseline_String3"
android:checked="true"
android:onClick="click"/>
</LinearLayout>
</LinearLayout>
5.java文件
src/BaseLineActivity.java
package com.antex.baseLine;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.ToggleButton;
public class BaseLineActivity extends AppCompatActivity {
private static final String TOGGLEBUTTON1_ISCHECKED="TOGGLEBUTTON1_ISCHECKED";
private static final String TOGGLEBUTTON2_ISCHECKED="TOGGLEBUTTON2_ISCHECKED";
private LinearLayout linearLayout1, linearLayout2;
private ToggleButton toggleButton1, toggleButton2;
@Override
protected void onCreate(Bundle savedInstanceState) {
System.out.println("BaseLineActivity.onCreate");
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_base_line);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
linearLayout1 = (LinearLayout) findViewById(R.id.ll_parent);
linearLayout2 = (LinearLayout) findViewById(R.id.ll_child);
toggleButton1 = (ToggleButton) findViewById(R.id.toggleButton1);
toggleButton2 = (ToggleButton) findViewById(R.id.toggleButton2);
//获取intent
Intent intent= getIntent();
//获取保存的ToggleButton状态
if(intent !=null) {
boolean b1=intent.getBooleanExtra(TOGGLEBUTTON1_ISCHECKED, true);
boolean b2=intent.getBooleanExtra(TOGGLEBUTTON2_ISCHECKED, true);
toggleButton1.setChecked(b1);
toggleButton2.setChecked(b2);
//setBaselineAligned(boolean) 是否允许用户调整它内容的基线。 true 允许按基线对齐,false不对齐
//只有带文本内容的控件才有基线,如TextView/Button/EditText
linearLayout1.setBaselineAligned(b1);
//setBaselineAlignedChildIndex(m) ,设置当前LinearLayout与其它View的对齐方式.
//索引号从0开始,表示是以第m+1控件为基准线与其它View对齐
linearLayout2.setBaselineAlignedChildIndex(b2 ? 3 : 0);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_base_line, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void click(View v) {
//直接修改不起作用
//linearLayout1.setBaselineAligned(toggleButton1.isChecked());
//linearLayout2.setBaselineAlignedChildIndex(toggleButton2.isChecked() ? 3 : 0);
//重启应用,并传入修改后的状态值
Intent intent= new Intent(BaseLineActivity.this,BaseLineActivity.class);
intent.putExtra(TOGGLEBUTTON1_ISCHECKED, toggleButton1.isChecked());
intent.putExtra(TOGGLEBUTTON2_ISCHECKED, toggleButton2.isChecked());
startActivity(intent);
finish();
}
}
开发工具:Android Studio1.4
SDK: Android 6.0
API 23
代码下载:BaseLine.zip