验证意图是否采取有效活动
验证意图是否采取有效活动
提问于 2018-06-24 16:39:18
public void action(View view){
Intent intent = new Intent(Settings.ACTION_DEVICE_INFO_SETTINGS);
if(intent!=null) //here is my problem, it return true always
{startActivity(intent);}
else{k++;
Context context = getApplicationContext();
CharSequence mesajText = "Failed To Open! " + k;
int duration = 3;
Toast screen_message = Toast.makeText(context,mesajText,duration);
screen_message.show();
}
}如何验证我的“意图”是否具有有效的活动(打开时有效)或无效的活动(打开时应用程序崩溃)？
回答 1
Stack Overflow用户
发布于 2018-06-24 17:33:29
if(intent!=null)将始终计算为true，因为您正在if condition之前初始化intent。如果您想检查是否可以处理Intent，请使用resolveActivity，如下所示：
Intent intent = new Intent(Settings.ACTION_DEVICE_INFO_SETTINGS);
PackageManager packageManager = getPackageManager();
if (intent.resolveActivity(packageManager) != null) {
startActivity(intent);
} else{
k++;
CharSequence mesajText = "Failed To Open! " + k;
int duration = 3;
Toast screen_message = Toast.makeText(this,mesajText,duration);
screen_message.show();
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/51008260
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