如何將我的代碼分成不同的文件，並在android中的onCreate方法中調用它們

Question

我正在創建一個基本的Android應用程序來學習。 下面我有創建在創建幾個textViews的主要活動。 我試圖通過將大量代碼放入另一個名為“ CreateCategories.java”的文件中，然后調用函數，類或運行該代碼的內容來清理項目。 我該怎么做呢？ 下面是我目前的程序

package com.company.practice;

import ...
.
.
import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

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

        RelativeLayout categoryLayout = findViewById(R.id.categoryContainer);

        ArrayList<Category> categories = new ArrayList<Category>();
        categories.add(new Category("rent", "0.35", "0.00"));
        categories.add(new Category("loan", "0.1", "0.00"));

        TextView[] catogoryTitleTextView = new TextView[categories.size()];
        TextView[] catogorypercentageTextView = new TextView[categories.size()];
        TextView[] catogoryAmountTextView = new TextView[categories.size()];
        for(int i =0; i < categories.size(); i++){
            //initialize textviews
            TextView title = new TextView(this);
            TextView percentage = new TextView(this);
            TextView amount = new TextView(this);

            //set text views text, id, and textsize
            title.setText(categories.get(i).title);
            //title.setTextSize(getResources().getDimension(R.dimen.textsize));
            title.setId(i + 100);
            percentage.setText(categories.get(i).percent);
            //percentage.setTextSize(getResources().getDimension(R.dimen.textsize));
            percentage.setId(i + 200);
            amount.setText(categories.get(i).amount);
            //amount.setTextSize(getResources().getDimension(R.dimen.textsize));
            amount.setId(i + 300);

            //set params for title textview
            RelativeLayout.LayoutParams titleParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
            titleParams.addRule(RelativeLayout.ALIGN_END, R.id.salaryCategoryTextVeiw);
            titleParams.height = RelativeLayout.LayoutParams.WRAP_CONTENT;
            titleParams.width = RelativeLayout.LayoutParams.WRAP_CONTENT;

            if(i==0){
                //set params for title textview if it the first one. it sets below the textveiw catagory, and has more margin
                titleParams.addRule(RelativeLayout.BELOW, R.id.salaryCategoryTextVeiw);
                titleParams.topMargin = 27;
            } else {
                //this will look up the id of teh last category text view
                titleParams.addRule(RelativeLayout.BELOW, catogoryTitleTextView[i-1].getId());
                titleParams.topMargin = 15;
            }

            title.setLayoutParams(titleParams);
            //set params for percentage textview
            RelativeLayout.LayoutParams PercentParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
            PercentParams.addRule(RelativeLayout.ALIGN_START, R.id.salaryPercentTextVeiw);
            PercentParams.addRule(RelativeLayout.ALIGN_TOP, title.getId());
            PercentParams.height = RelativeLayout.LayoutParams.WRAP_CONTENT;
            PercentParams.width = RelativeLayout.LayoutParams.WRAP_CONTENT;

            percentage.setLayoutParams(PercentParams);

            //set params for amount textview
            RelativeLayout.LayoutParams AmountParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
            AmountParams.addRule(RelativeLayout.ALIGN_START, R.id.salaryAmountTextVeiw);
            AmountParams.addRule(RelativeLayout.ALIGN_TOP, percentage.getId());
            AmountParams.height = RelativeLayout.LayoutParams.WRAP_CONTENT;
            AmountParams.width = RelativeLayout.LayoutParams.WRAP_CONTENT;

            amount.setLayoutParams(AmountParams);

            //add text views to layout
            categoryLayout.addView(title);
            categoryLayout.addView(percentage);
            categoryLayout.addView(amount);


            //save the views within the arrays
            catogoryTitleTextView[i] = title;
            catogorypercentageTextView[i] = percentage;
            catogoryAmountTextView[i] = amount;
        }
    }
}

我希望它看起來像這樣：MainActivty.java

package com.company.practice;

import ...
.
.
import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

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

CreateCategories.java

Function CreateCategories() {
    RelativeLayout categoryLayout = findViewById(R.id.categoryContainer);

    ArrayList<Category> categories = new ArrayList<Category>();
        categories.add(new Category("rent", "0.35", "0.00"));
        categories.add(new Category("loan", "0.1", "0.00"));

    TextView[] catogoryTitleTextView = new TextView[categories.size()];
    TextView[] catogorypercentageTextView = new TextView[categories.size()];
    TextView[] catogoryAmountTextView = new TextView[categories.size()];
        for(int i =0; i < categories.size(); i++){
        //initialize textviews
        TextView title = new TextView(this);
        TextView percentage = new TextView(this);
        TextView amount = new TextView(this);

        //set text views text, id, and textsize
        title.setText(categories.get(i).title);
        //title.setTextSize(getResources().getDimension(R.dimen.textsize));
        title.setId(i + 100);
        percentage.setText(categories.get(i).percent);
        //percentage.setTextSize(getResources().getDimension(R.dimen.textsize));
        percentage.setId(i + 200);
        amount.setText(categories.get(i).amount);
        //amount.setTextSize(getResources().getDimension(R.dimen.textsize));
        amount.setId(i + 300);

        //set params for title textview
        RelativeLayout.LayoutParams titleParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
        titleParams.addRule(RelativeLayout.ALIGN_END, R.id.salaryCategoryTextVeiw);
        titleParams.height = RelativeLayout.LayoutParams.WRAP_CONTENT;
        titleParams.width = RelativeLayout.LayoutParams.WRAP_CONTENT;

        if(i==0){
            //set params for title textview if it the first one. it sets below the textveiw catagory, and has more margin
            titleParams.addRule(RelativeLayout.BELOW, R.id.salaryCategoryTextVeiw);
            titleParams.topMargin = 27;
        } else {
            //this will look up the id of teh last category text view
            titleParams.addRule(RelativeLayout.BELOW, catogoryTitleTextView[i-1].getId());
            titleParams.topMargin = 15;
        }

        title.setLayoutParams(titleParams);
        //set params for percentage textview
        RelativeLayout.LayoutParams PercentParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
        PercentParams.addRule(RelativeLayout.ALIGN_START, R.id.salaryPercentTextVeiw);
        PercentParams.addRule(RelativeLayout.ALIGN_TOP, title.getId());
        PercentParams.height = RelativeLayout.LayoutParams.WRAP_CONTENT;
        PercentParams.width = RelativeLayout.LayoutParams.WRAP_CONTENT;

        percentage.setLayoutParams(PercentParams);

        //set params for amount textview
        RelativeLayout.LayoutParams AmountParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
        AmountParams.addRule(RelativeLayout.ALIGN_START, R.id.salaryAmountTextVeiw);
        AmountParams.addRule(RelativeLayout.ALIGN_TOP, percentage.getId());
        AmountParams.height = RelativeLayout.LayoutParams.WRAP_CONTENT;
        AmountParams.width = RelativeLayout.LayoutParams.WRAP_CONTENT;

        amount.setLayoutParams(AmountParams);

        //add text views to layout
        categoryLayout.addView(title);
        categoryLayout.addView(percentage);
        categoryLayout.addView(amount);


        //save the views within the arrays
        catogoryTitleTextView[i] = title;
        catogorypercentageTextView[i] = percentage;
        catogoryAmountTextView[i] = amount;
    }

任何有關如何執行此操作的有用建議將不勝感激。

Answer 1

您將必須實現一個將執行該工作的類，而您所要做的就是初始化您創建的類的對象並調用該類的特定功能。 如果您需要創建一些Toast或其他內容，則將上下文傳遞給該函數並在該函數中進行Toast。 但是不要忘記，您必須定義一個公共靜態上下文才能從外部類訪問它。

Answer 2

您正在做很多工作，以使代碼“更有條理”，但可讀性差得多。

要執行您想做的事情，您必須創建一個“庫”類（從不實例化，僅包含靜態方法），該類包含一個靜態函數，您可以從主onCreate調用它，並以某種方式返回實例化的所有內容，就像ArrayList，一個RelativeLayout和3個TextView數組，將它們分配給調用類中的變量，以便實例化它們后就可以使用它們。

如果要清理onCreate，請務必將代碼重構為另一個函數，放在同一類中，希望在原始代碼所在的位置附近，這樣，當您忘記值的位置時，不必在兩個文件之間查找在您的庫函數中創建的文件來自。

將代碼真正移入靜態庫函數的唯一時間是，如果您需要從多個類訪問該代碼多次。