Question

我有两个活动，MainActivity和SecondActivity。将int值从MainActivity传递给SecondActivity时，它变为“0”。我已尝试使用和不使用bundle，尝试了StackOverFlow上已有的各种解决方案，但没有去。

这是我的代码： MainActivity

final Intent intent = new Intent(MainActivity.this, SecondActivity.class);

    final TextView textView = findViewById(R.id.textView);
    textView.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v){
            Bundle bundle = new Bundle();
            bundle.putInt("category",9);
            intent.putExtras(bundle); 
            startActivity(intent);
        }
    });

SecondActivity：

    package com.example.app;

    import android.content.Intent;
    import android.support.v4.view.ViewPager;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;


    public class SecondActivity extends AppCompatActivity {   

    ViewPager viewPager;
    TabsPagerAdapter pagerAdapter;
    private int mMedCategory = 6;

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

       // String stringCategory = getIntent().getStringExtra("category_string");
    int medCategory = getIntent().getIntExtra("category_int", -1);
    setMedCategory(medCategory);

    viewPager = findViewById(R.id.viewpager);
    pagerAdapter = new TabsPagerAdapter(getSupportFragmentManager());
    viewPager.setAdapter(pagerAdapter);

    }
    public int getMedCategory(){
        return mMedCategory; //This value goes to TabsPagerAdapter
    }

    public void setMedCategory(int i){
        mMedCategory = i;
    }
    }

Answer 1

使用Intent#getIntExtra()从意图中检索整数值：

来自MainActivity：

Intent myIntent = new Intent(MainActivity.this, SecondActivity.class);
myIntent.putExtra("category", 9);
MainActivity.this.startActivity(myIntent);

来自SecondActivity：

@Override
protected void onCreate(Bundle savedInstanceState) {
    Intent intent = getIntent();
    medCategory = intent.getIntExtra("category", -1);
}

请注意，如果无法找到密钥，这会将-1的默认值分配给medCategory。

Answer 2

你可以试试这个：

<强> MainActivity

Error: spawn EACCES
at exports._errnoException (util.js:1026:11)
at ChildProcess.spawn (internal/child_process.js:313:11)
at Object.exports.spawn (child_process.js:380:9)
at module.exports (/home/dothmobi/public_html/demo/drivzi_admin/materialadmin/material/node_modules/opn/index.js:75:24)
at Object.open (/home/dothmobi/public_html/demo/drivzi_admin/materialadmin/material/node_modules/browser-sync/lib/utils.js:186:9)
at Object.openBrowser (/home/dothmobi/public_html/demo/drivzi_admin/materialadmin/material/node_modules/browser-sync/lib/utils.js:165:23)
at EventEmitter.service:running (/home/dothmobi/public_html/demo/drivzi_admin/materialadmin/material/node_modules/browser-sync/lib/internal-events.js:42:23)
at emitOne (events.js:101:20)
at EventEmitter.emit (events.js:188:7)
at /home/dothmobi/public_html/demo/drivzi_admin/materialadmin/material/node_modules/browser-sync/lib/browser-sync.js:260:19

<强> SecondActivity

TextView textView = findViewById(R.id.textView);
textView.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {

        Intent intent = new Intent(MainActivity.this, SecondActivity.class);
        intent.putExtra("category_int", 9);
        intent.putExtra("category_string", "9");
        startActivity(intent);
    }
});

您可以查看How do I pass data between Activities in Android application?

Answer 3

使用此代码。删除final并尝试在onclick方法中初始化意图而不是在它之外。

在您的OnClick

Intent intent=new Intent(this,Main2Activity.class);
    Bundle bundle = new Bundle();
    bundle.putInt("category",9);
    intent.putExtras(bundle);
    startActivity(intent);

在您的第二个活动中

public class Main2Activity extends AppCompatActivity {

private int mMedCategory =0;

public int getmMedCategory() {
    return mMedCategory;
}

public void setmMedCategory(int mMedCategory) {
    this.mMedCategory = mMedCategory;
}

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

    Bundle bundle=getIntent().getExtras();
    if(bundle!=null){
        int demoCategory =bundle.getInt("category");
        setmMedCategory(demoCategory);
    }else {
        Toast.makeText(this, "null", Toast.LENGTH_SHORT).show();
    }
}

public void Show(View view) {
    Toast.makeText(this, String.valueOf(getmMedCategory()), Toast.LENGTH_SHORT).show();
}

}

修改

为您创建了一个演示项目。显示方法是按钮的onclick方法。

Answer 4

我不确定，但您可以将其用于第二项活动：

SecondActivity secondActivity = new SecondActivity();
    if (secondActivity.getIntent.getExtras() != null)
    {
        int medCat = secondActivity.getIntent.getExtras().getInt("category");
    }

从一个活动传递到另一个活动时，int / string值变为“0”/ null

4 个答案: