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[英]Pass a XML resource from one activity to another activity using java code in Android Studio?
[英]How do I add button to another activity in android studio using java code rather than xml code
我想使用 Z93F725A07423FE1C889F448B33D2 代码从 1 个活动 -“ pop_accompaniments.xml ”添加一个按钮到另一个活动 -“ pop_cart.xml ”。 For this I created an instance of the class " pop_cart.java " in " pop_accompaniments.java ", to call the func - "cart_button_creator" which is in " pop_cart.java ". 但是我的应用程序一打开就崩溃了。
pop_accompaniments.java
package com.example.myapplication;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import androidx.appcompat.app.AppCompatActivity;
import java.util.Random;
public class pop_accompaniments extends AppCompatActivity implements View.OnClickListener {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.pop_accompaniments);
Button assorted_condiments = findViewById(R.id.assorted_condiments);
}
@Override
public void onClick(View v) {
setContentView(R.layout.pop_cart);
pop_cart main = new pop_cart();
int id;
String name;
Button myButton;
switch (v.getId()) {
case R.id.assorted_condiments:
myButton = new Button(this);
name = "Assorted Condiments";
id = generateButtonId();
main.cart_content_keeper(id, name, myButton);
}
}
}
pop_cart.java
package com.example.myapplication;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;
import androidx.annotation.Nullable;
public class pop_cart extends Activity {
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.pop_cart);
}
public void cart_button_creator(String name, int id, Button myButton) {
//setContentView(R.layout.pop_cart);
LinearLayout ll = findViewById(R.id.cart_items);
myButton.setText(name);
myButton.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
myButton.setId(id);
ll.addView(myButton);
}
public void cart_content_keeper(int id, String name, final Button myButton) {
int n = 0;
int[] id_arr = {};
String[] name_arr = {};
//int price = 0;
name_arr = add_item(n, name_arr, name);
id_arr = add_id(n, id_arr, id);
n = n + 1;
Button refresh = findViewById(R.id.refresh);
final int finalN = n;
final String[] finalName_arr = name_arr;
final int[] finalId_arr = id_arr;
refresh.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (v.getId() == R.id.refresh) {
for (int i = 0; i < finalN; i++) {
cart_button_creator(finalName_arr[i], finalId_arr[i], myButton);
}
}
}
});
}
public static String[] add_item(int n, String[] arr, String x)
{
int i;
String[] newarr = new String[n + 1];
for (i = 0; i < n; i++)
newarr[i] = arr[i];
newarr[n] = x;
return newarr;
}
public static int[] add_id(int n, int[] arr, int x)
{
int i;
int[] newarr = new int[n + 1];
for (i = 0; i < n; i++)
newarr[i] = arr[i];
newarr[n] = x;
return newarr;
}
}
抱歉这么长的代码,但我已经尝试了几乎所有可能的方法来从另一个 class 的实例调用函数,以不同的方式传递变量,尝试将整个变量生成器调用为 function 并且只传递视图 v作为 pop_accompaniments.java 中的一个参数,但是当我在第一步单击“ASSORTED CONDIMENTS”按钮时,或者如果我只是启动应用程序,应用程序就会崩溃。
此外,如果我在从“ pop_accompaniments.java ”调用 button_creator 方法的同时在“ pop_accompaniments.xml ”的同一活动中创建按钮,则这些按钮创建得很好。
但我希望他们显示在 CART 活动中,而不是 ACCOMPANIMENTS 活动中。
我猜您需要在活动 pop_cart.java 处于前台时创建按钮。 那么为什么不直接执行pop_cart.java的onCreate()中的按钮代码呢?
You can pass a boolean from pop_accompaniments.java to pop_cart.java via an intent if you want something in pop_accompaniments.java to decide whether the button will be created or not!
在 pop_accompaniments.java 中:
Intent intent = new Intent(this, pop_cart.class);
intent.putExtra("someBool", true);
在 pop_cart.java 中:
@Override
protected void onCreate(Bundle savedInstanceState) {
Boolean bool = getIntent().getExtras().getBoolean("someBool");
//Now you can check if the bool is true or false
if(bool){
//Execute button code here
}
}
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