Question

我想从一个活动传递一个整数到另一个活动并在textView Widget中显示整数，构建中没有错误但在logcat中有6个错误。我是android的初学者，我不知道这么多。请指导。

我想 go＆amp;将整数从一个活动发送到另一个活动按一个按钮。

MainActivity.java

    package com.ghermez.sibe.salary_usd;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import static java.lang.Integer.*;


public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Button B1 =  findViewById(R.id.button1);
    B1.setOnClickListener(new OnClickListener() {

        EditText et_tusd = findViewById(R.id.tusd);
        int tusd = parseInt(et_tusd.getText().toString());\

        @Override
        public void onClick(View v) {
            Intent i=new Intent(MainActivity.this,Main2Activity.class);
            startActivity(i);

            Intent i1 = new Intent(MainActivity.this,Main2Activity.class);
            i1.putExtra("i1",tusd);
            startActivity(i1);

        }

    });
}

}

Main2Activity.java

    package com.ghermez.sibe.salary_usd;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.TextView;

public class Main2Activity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);

    Intent i1s = getIntent();
    Integer tusd = i1s.getIntExtra("i1",0);

    EditText editText_tusd = findViewById(R.id.tusd);
    editText_tusd.setText(tusd, TextView.BufferType.EDITABLE);
    }
}

我的应用程序无法在虚拟设备上运行。它在logcat中有6个错误：

logcat的

04-21 16:43:13.526 5433-5433/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.ghermez.sibe.salary_usd, PID: 5433
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.ghermez.sibe.salary_usd/com.ghermez.sibe.salary_usd.MainActivity}: java.lang.NumberFormatException: For input string: ""
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2817)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)
    at android.app.ActivityThread.-wrap11(Unknown Source:0)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)
    at android.os.Handler.dispatchMessage(Handler.java:105)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6541)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
 Caused by: java.lang.NumberFormatException: For input string: ""
    at java.lang.Integer.parseInt(Integer.java:620)
    at java.lang.Integer.parseInt(Integer.java:643)
    at com.ghermez.sibe.salary_usd.MainActivity$1.<init>(MainActivity.java:26)
    at com.ghermez.sibe.salary_usd.MainActivity.onCreate(MainActivity.java:22)
    at android.app.Activity.performCreate(Activity.java:6975)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1213)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2770)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892) 
    at android.app.ActivityThread.-wrap11(Unknown Source:0) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593) 
    at android.os.Handler.dispatchMessage(Handler.java:105) 
    at android.os.Looper.loop(Looper.java:164) 
    at android.app.ActivityThread.main(ActivityThread.java:6541) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

Answer 1

看来，传递给tusd的{{1}}字符串的整数格式错误。

在这里你把它放到Intent：

Main2Activity

在这里你可以从Intent获得它：

i1.putExtra("i1",tusd);

logcat说传递的字符串有错误的整数格式：

Integer tusd = i1s.getIntExtra("i1",0);

尝试检查Caused by: java.lang.NumberFormatException: For input string: ""中的tusd字符串。

无法启动活动ComponentInfo {}; java.lang.NumberFormatException：对于输入字符串：

1 个答案: