第一章:初入Android大门(不同的Activity之间的数据传递)

效果


[img]http://dl.iteye.com/upload/attachment/378855/5f343400-4c46-3305-a83e-558a99a037f2.jpg[/img]


[img]http://dl.iteye.com/upload/attachment/378857/a6d56289-87f4-3a47-9d03-12fe4f4b5bc9.jpg[/img]

来设置第一个Activity
main.xml

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

<EditText
android:id="@+id/heigths"
android:layout_width="129px"
android:layout_height="wrap_content"
android:textSize="18sp"
android:layout_x="122px"
android:layout_y="141px"
>
</EditText>
<RadioGroup android:id="@+id/sexs"
        android:layout_width="wrap_content"
		android:layout_x="122px"
		android:orientation="horizontal"
		android:layout_y="87px"
        android:layout_height="wrap_content">
<RadioButton
android:id="@+id/boy"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="男"
>
</RadioButton>
<RadioButton
android:id="@+id/gril"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="女"
>
</RadioButton>
</RadioGroup>
<TextView
android:id="@+id/sexText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="性别:"
android:layout_x="51px"
android:layout_y="102px"
>
</TextView>
<TextView
android:id="@+id/heigth"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="身高:"
android:layout_x="51px"
android:layout_y="152px"
>
</TextView>
<Button
android:id="@+id/count"
android:layout_width="74px"
android:layout_height="wrap_content"
android:text="计算"
android:layout_x="140px"
android:layout_y="203px"
>
</Button>
</AbsoluteLayout>

设置第二个Activity新建一个layout2.xml文件

<?xml version="1.0" encoding="utf-8"?>
<AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
android:id="@+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="性别:"
android:layout_x="74px"
android:layout_y="106px"
>
</TextView>


</AbsoluteLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="transfer.data"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity 
        		  android:name=".TransferData"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
		<activity android:name=".TransferData2"></activity>
    </application>
</manifest> 

在来看看R.java

/* AUTO-GENERATED FILE.  DO NOT MODIFY.
 *
 * This class was automatically generated by the
 * aapt tool from the resource data it found.  It
 * should not be modified by hand.
 */

package transfer.data;

public final class R {
    public static final class attr {
    }
    public static final class drawable {
        public static final int icon=0x7f020000;
    }
    public static final class id {
        public static final int boy=0x7f050003;
        public static final int count=0x7f050007;
        public static final int gril=0x7f050004;
        public static final int heigth=0x7f050006;
        public static final int heigths=0x7f050001;
        public static final int sexText=0x7f050005;
        public static final int sexs=0x7f050002;
        public static final int text=0x7f050000;
    }
    public static final class layout {
        public static final int layout2=0x7f030000;
        public static final int main=0x7f030001;
    }
    public static final class string {
        public static final int app_name=0x7f040001;
        public static final int hello=0x7f040000;
    }
}

好了配置完了接下来开始写代码了

package transfer.data;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;

public class TransferData extends Activity {
    /** Called when the activity is first created. */
	private Button bt;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        /**载入main.xml*/
        setContentView(R.layout.main);
        /**找到计算按钮*/
        bt=(Button)findViewById(R.id.count);
        /**设置按钮的监听事件*/
        bt.setOnClickListener(new Button.OnClickListener(){
        	public void onClick(View v){
        		/**找到文本框*/
        		EditText et=(EditText)findViewById(R.id.heigths);
        		/**将文本框的值转换为 double类型的*/
        		double height=Double.parseDouble(et.getText().toString());
        		String sex="";
        		/**找到单选按钮*/
        		RadioButton rb1=(RadioButton)findViewById(R.id.boy);
        		/**判断是否被选中*/
        		if(rb1.isChecked()){
        			sex="男";
        		}else{
        			sex="女";
        		}
        		/**实例化Intent对像,并指定传递的class*/
        		Intent intent=new Intent();
        		intent.setClass(TransferData.this, TransferData2.class);

        		/**实例化Bundle对像,把将要传递的数据以键值对的形式添加进去*/
        		Bundle bundle=new Bundle();
        		/**添加的是Double类型的数值*/
        		bundle.putDouble("height", height);
        		/**添加的是String类型的数值*/
        		bundle.putString("sex", sex);
        		/**将设置好值的Bundle对象添加进Intent*/
        		intent.putExtras(bundle);
        		/**调用TransferData2 传递开始*/
        		startActivity(intent);
        	}
        });
    }
}

package transfer.data;

import java.text.DecimalFormat;
import java.text.NumberFormat;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class TransferData2 extends Activity {
	public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        /**载入layout*/
        setContentView(R.layout.layout2);
        /**获取 Bundle对象*/
        Bundle bundle=this.getIntent().getExtras();
        /**获取 传递过来的值也就是性别*/
        String sex=bundle.getString("sex");
        /**获取 传递过来的值身高*/
        double height=bundle.getDouble("height");
        /**通过id找到TextView组件对象*/
        TextView text=(TextView)findViewById(R.id.text);
        /**设置TextView的文本值*/
        text.setText("性别:"+sex+"\n身高:"+height+"\n标准体重:"+getWeight(sex, height));
	}

	public String format(double num){
		NumberFormat formatter=new DecimalFormat("0.00");
		String count=formatter.format(num);
		return count;
	}
	/**计算男女标准体重*/
	public String getWeight(String sex,double height){
		String weight="";
		weight=format((height-80)*0.7);
		if(sex.equals("男")){
			weight=format((height-70)*0.7);
		}
		return weight;
	}
}