Android 无法访问另一个活动中一个活动的变量
我的第一个活动包括以下代码Android 无法访问另一个活动中一个活动的变量,android,variables,android-activity,Android,Variables,Android Activity,我的第一个活动包括以下代码 mHandler.postDelayed(mLaunchTask,10000); private Runnable mLaunchTask = new Runnable() { public void run() { Intent i = new Intent(getApplicationContext(),NearestPoint.cl
mHandler.postDelayed(mLaunchTask,10000);
private Runnable mLaunchTask = new Runnable()
{
public void run()
{
Intent i = new Intent(getApplicationContext(),NearestPoint.class);
Bundle params = new Bundle();
params.putFloat("latiA", latA);
params.putFloat("longiA", longA);
params.putFloat("latiB", latB);
params.putFloat("longiB", longB);
params.putFloat("latiC", latC);
params.putFloat("longiC", longC);
i.putExtras(params);
startActivity(i);
}
};
最近点的活动包括此代码
public float latA, longA, latB, longB, latC, longC;
Intent it = getIntent(); {
if (it != null)
{
Bundle params = it.getExtras();
if (params != null)
{
latA = params.getFloat("latiA");
longA = params.getFloat("longiA");
latB = params.getFloat("latiB");
longB = params.getFloat("longiB");
latC = params.getFloat("latiC");
longC = params.getFloat("longiC");
}
}}
我无法在最近点活动中正确访问latA、longA等值。
我尝试使用Toast显示:
Toast.makeText(getApplicationContext(),"\nPoint A: \nLatitude: " + latA + "\nLongitude: " + longA, Toast.LENGTH_LONG).show();
在FirstActivity中,它给出了正确的值,但在最近的点上,我得到的纬度和经度都是0.0
这是我的舱单:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.gpsdistance"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="16" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.gpsdistance.FirstActivity"
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="com.example.gpsdistance.NearestPoint"
android:label="@string/title_activity_nearest_point" >
</activity>
<activity
android:name="com.example.gpsdistance.MinimumDistance"
android:label="@string/title_activity_minimum_distance" >
</activity>
</application>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />
</manifest>
请提供帮助。发生这种情况是因为在实例化可运行时,latA、longA、latB、longB、latC、longC的值为零。您应该为每个值使用一个getter,如下所示:
mHandler.postDelayed(mLaunchTask,10000);
private Runnable mLaunchTask = new Runnable()
{
public void run()
{
Intent i = new Intent(getApplicationContext(),NearestPoint.class);
Bundle params = new Bundle();
params.putFloat("latiA", getLatiA()); //You should to call a getter here
i.putExtras(params);
startActivity(i);
}
};
//In your class
private double getLatiA() {
return this.latiA;
}
我不明白你为什么在另一个线程中运行活动。我建议使用服务 我可以看看你的清单文件吗。因为我刚刚尝试了这个示例,它对我来说运行良好。我添加了清单文件。我还添加了FirstActivity类中的完整代码。进行测试。在runnable中放入一个硬代码值,以查看该值是否已发送。如参数putFloat(“latiA”,21.4);您最近的点试图从intent获取额外值的方法是什么?方法是points()。它在班级活动中。我已经添加了完整项目的链接。一定要看一看。我尝试通过构造函数获取值,但即使这样也不起作用。
mHandler.postDelayed(mLaunchTask,10000);
private Runnable mLaunchTask = new Runnable()
{
public void run()
{
Intent i = new Intent(getApplicationContext(),NearestPoint.class);
Bundle params = new Bundle();
params.putFloat("latiA", getLatiA()); //You should to call a getter here
i.putExtras(params);
startActivity(i);
}
};
//In your class
private double getLatiA() {
return this.latiA;
}